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Wikipedia

Phosphor

A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light, and cathodoluminescent substances which glow when struck by an electron beam (cathode rays) in a cathode-ray tube.

Example of phosphorescence
Monochrome monitor
Aperture grille CRT phosphors

When a phosphor is exposed to radiation, the orbital electrons in its molecules are excited to a higher energy level; when they return to their former level they emit the energy as light of a certain color. Phosphors can be classified into two categories: fluorescent substances which emit the energy immediately and stop glowing when the exciting radiation is turned off, and phosphorescent substances which emit the energy after a delay, so they keep glowing after the radiation is turned off, decaying in brightness over a period of milliseconds to days.

Fluorescent materials are used in applications in which the phosphor is excited continuously: cathode-ray tubes (CRT) and plasma video display screens, fluoroscope screens, fluorescent lights, scintillation sensors, white LEDs, and luminous paints for black light art. Phosphorescent materials are used where a persistent light is needed, such as glow-in-the-dark watch faces and aircraft instruments, and in radar screens to allow the target 'blips' to remain visible as the radar beam rotates. CRT phosphors were standardized beginning around World War II and designated by the letter "P" followed by a number.

Phosphorus, the light-emitting chemical element for which phosphors are named, emits light due to chemiluminescence, not phosphorescence.[1]

Light-emission process edit

 
Jablonski diagram shows the energy levels in a fluorescing atom in a phosphor. An electron in the phosphor absorbs a high-energy photon from the applied radiation, exciting it to a higher energy level. After losing some energy in non-radiative transitions, it eventually transitions back to its ground state energy level by fluorescence, emitting a photon of lower energy in the visible light region.

The scintillation process in inorganic materials is due to the electronic band structure found in the crystals. An incoming particle can excite an electron from the valence band to either the conduction band or the exciton band (located just below the conduction band and separated from the valence band by an energy gap). This leaves an associated hole behind, in the valence band. Impurities create electronic levels in the forbidden gap. The excitons are loosely bound electron–hole pairs that wander through the crystal lattice until they are captured as a whole by impurity centers. The latter then rapidly de-excite by emitting scintillation light (fast component). In the case of inorganic scintillators, the activator impurities are typically chosen so that the emitted light is in the visible range or near-UV, where photomultipliers are effective. The holes associated with electrons in the conduction band are independent from the latter. Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons. The delayed de-excitation of those metastable impurity states, slowed by reliance on the low-probability forbidden mechanism, again results in light emission (slow component).

Phosphors are often transition-metal compounds or rare-earth compounds of various types. In inorganic phosphors, these inhomogeneities in the crystal structure are created usually by addition of a trace amount of dopants, impurities called activators. (In rare cases dislocations or other crystal defects can play the role of the impurity.) The wavelength emitted by the emission center is dependent on the atom itself and on the surrounding crystal structure.

Materials edit

Phosphors are usually made from a suitable host material with an added activator. The best known type is a copper-activated zinc sulfide (ZnS) and the silver-activated zinc sulfide (zinc sulfide silver).

The host materials are typically oxides, nitrides and oxynitrides,[2] sulfides, selenides, halides or silicates of zinc, cadmium, manganese, aluminium, silicon, or various rare-earth metals. The activators prolong the emission time (afterglow). In turn, other materials (such as nickel) can be used to quench the afterglow and shorten the decay part of the phosphor emission characteristics.

Many phosphor powders are produced in low-temperature processes, such as sol-gel, and usually require post-annealing at temperatures of ~1000 °C, which is undesirable for many applications. However, proper optimization of the growth process allows manufacturers to avoid the annealing.[3]

Phosphors used for fluorescent lamps require a multi-step production process, with details that vary depending on the particular phosphor. Bulk material must be milled to obtain a desired particle size range, since large particles produce a poor-quality lamp coating, and small particles produce less light and degrade more quickly. During the firing of the phosphor, process conditions must be controlled to prevent oxidation of the phosphor activators or contamination from the process vessels. After milling, the phosphor may be washed to remove minor excess of activator elements. Volatile elements must not be allowed to escape during processing. Lamp manufacturers have changed compositions of phosphors to eliminate some toxic elements, such as beryllium, cadmium, or thallium, formerly used.[4]

The commonly quoted parameters for phosphors are the wavelength of emission maximum (in nanometers, or alternatively color temperature in kelvins for white blends), the peak width (in nanometers at 50% of intensity), and decay time (in seconds).

Examples:

  • Calcium sulfide with strontium sulfide with bismuth as activator, (Ca,Sr)S:Bi, yields blue light with glow times up to 12 hours, red and orange are modifications of the zinc sulfide formula. Red color can be obtained from strontium sulfide.
  • Zinc sulfide with about 5 ppm of a copper activator is the most common phosphor for the glow-in-the-dark toys and items. It is also called GS phosphor.
  • Mix of zinc sulfide and cadmium sulfide emit color depending on their ratio; increasing of the CdS content shifts the output color towards longer wavelengths; its persistence ranges between 1–10 hours.
  • Strontium aluminate activated by europium, SrAl2O4:Eu(II):Dy(III), is a material developed in 1993 by Nemoto & Co. engineer Yasumitsu Aoki with higher brightness and significantly longer glow persistence; it produces green and aqua hues, where green gives the highest brightness and aqua the longest glow time.[5][6] SrAl2O4:Eu:Dy is about 10 times brighter, 10 times longer glowing, and 10 times more expensive than ZnS:Cu.[5] The excitation wavelengths for strontium aluminate range from 200 to 450 nm. The wavelength for its green formulation is 520 nm, its blue-green version emits at 505 nm, and the blue one emits at 490 nm. Colors with longer wavelengths can be obtained from the strontium aluminate as well, though for the price of some loss of brightness.

Phosphor degradation edit

Many phosphors tend to lose efficiency gradually by several mechanisms. The activators can undergo change of valence (usually oxidation), the crystal lattice degrades, atoms – often the activators – diffuse through the material, the surface undergoes chemical reactions with the environment with consequent loss of efficiency or buildup of a layer absorbing either the exciting or the radiated energy, etc.

The degradation of electroluminescent devices depends on frequency of driving current, the luminance level, and temperature; moisture impairs phosphor lifetime very noticeably as well.

Harder, high-melting, water-insoluble materials display lower tendency to lose luminescence under operation.[7]

Examples:

  • BaMgAl10O17:Eu2+ (BAM), a plasma-display phosphor, undergoes oxidation of the dopant during baking. Three mechanisms are involved; absorption of oxygen atoms into oxygen vacancies on the crystal surface, diffusion of Eu(II) along the conductive layer, and electron transfer from Eu(II) to absorbed oxygen atoms, leading to formation of Eu(III) with corresponding loss of emissivity.[8] Thin coating of aluminium phosphate or lanthanum(III) phosphate is effective in creating a barrier layer blocking access of oxygen to the BAM phosphor, for the cost of reduction of phosphor efficiency.[9] Addition of hydrogen, acting as a reducing agent, to argon in the plasma displays significantly extends the lifetime of BAM:Eu2+ phosphor, by reducing the Eu(III) atoms back to Eu(II).[10]
  • Y2O3:Eu phosphors under electron bombardment in presence of oxygen form a non-phosphorescent layer on the surface, where electron–hole pairs recombine nonradiatively via surface states.[11]
  • ZnS:Mn, used in AC thin-film electroluminescent (ACTFEL) devices degrades mainly due to formation of deep-level traps, by reaction of water molecules with the dopant; the traps act as centers for nonradiative recombination. The traps also damage the crystal lattice. Phosphor aging leads to decreased brightness and elevated threshold voltage.[12]
  • ZnS-based phosphors in CRTs and FEDs degrade by surface excitation, coulombic damage, build-up of electric charge, and thermal quenching. Electron-stimulated reactions of the surface are directly correlated to loss of brightness. The electrons dissociate impurities in the environment, the reactive oxygen species then attack the surface and form carbon monoxide and carbon dioxide with traces of carbon, and nonradiative zinc oxide and zinc sulfate on the surface; the reactive hydrogen removes sulfur from the surface as hydrogen sulfide, forming nonradiative layer of metallic zinc. Sulfur can be also removed as sulfur oxides.[13]
  • ZnS and CdS phosphors degrade by reduction of the metal ions by captured electrons. The M2+ ions are reduced to M+; two M+ then exchange an electron and become one M2+ and one neutral M atom. The reduced metal can be observed as a visible darkening of the phosphor layer. The darkening (and the brightness loss) is proportional to the phosphor's exposure to electrons and can be observed on some CRT screens that displayed the same image (e.g. a terminal login screen) for prolonged periods.[14]
  • Europium(II)-doped alkaline earth aluminates degrade by formation of color centers.[7]
  • Y
    2
    SiO
    5
    :Ce3+ degrades by loss of luminescent Ce3+ ions.[7]
  • Zn
    2
    SiO
    4
    :Mn (P1) degrades by desorption of oxygen under electron bombardment.[7]
  • Oxide phosphors can degrade rapidly in presence of fluoride ions, remaining from incomplete removal of flux from phosphor synthesis.[7]
  • Loosely packed phosphors, e.g. when an excess of silica gel (formed from the potassium silicate binder) is present, have tendency to locally overheat due to poor thermal conductivity. E.g. InBO
    3
    :Tb3+ is subject to accelerated degradation at higher temperatures.[7]

Applications edit

Lighting edit

Phosphor layers provide most of the light produced by fluorescent lamps, and are also used to improve the balance of light produced by metal halide lamps. Various neon signs use phosphor layers to produce different colors of light. Electroluminescent displays found, for example, in aircraft instrument panels, use a phosphor layer to produce glare-free illumination or as numeric and graphic display devices. White LED lamps consist of a blue or ultra-violet emitter with a phosphor coating that emits at longer wavelengths, giving a full spectrum of visible light. Unfocused and undeflected cathode-ray tubes have been used as stroboscope lamps since 1958.[15]

Phosphor thermometry edit

Phosphor thermometry is a temperature measurement approach that uses the temperature dependence of certain phosphors. For this, a phosphor coating is applied to a surface of interest and, usually, the decay time is the emission parameter that indicates temperature. Because the illumination and detection optics can be situated remotely, the method may be used for moving surfaces such as high speed motor surfaces. Also, phosphor may be applied to the end of an optical fiber as an optical analog of a thermocouple.[citation needed]

Glow-in-the-dark toys edit

In these applications, the phosphor is directly added to the plastic used to mold the toys, or mixed with a binder for use as paints.

ZnS:Cu phosphor is used in glow-in-the-dark cosmetic creams frequently used for Halloween make-ups. Generally, the persistence of the phosphor increases as the wavelength increases. See also lightstick for chemiluminescence-based glowing items.

Oxygen sensing edit

Quenching of the triplet state by O2 (which has a triplet ground state) as a result of Dexter energy transfer is well known in solutions of phosphorescent heavy-metal complexes and doped polymers.[16] In recent years, phosphorescence porous materials(such as Metal–organic frameworks and Covalent organic frameworks) have shown promising oxygen sensing capabilities, for their non-linear gas-adsorption in ultra-low partial pressures of oxygen.[17][18]

Postage stamps edit

Phosphor banded stamps first appeared in 1959 as guides for machines to sort mail.[19] Around the world many varieties exist with different amounts of banding.[20] Postage stamps are sometimes collected by whether or not they are "tagged" with phosphor (or printed on luminescent paper).

Radioluminescence edit

Zinc sulfide phosphors are used with radioactive materials, where the phosphor was excited by the alpha- and beta-decaying isotopes, to create luminescent paint for dials of watches and instruments (radium dials). Between 1913 and 1950 radium-228 and radium-226 were used to activate a phosphor made of silver doped zinc sulfide (ZnS:Ag), which gave a greenish glow. The phosphor is not suitable to be used in layers thicker than 25 mg/cm2, as the self-absorption of the light then becomes a problem. Furthermore, zinc sulfide undergoes degradation of its crystal lattice structure, leading to gradual loss of brightness significantly faster than the depletion of radium. ZnS:Ag coated spinthariscope screens were used by Ernest Rutherford in his experiments discovering atomic nucleus.

Copper doped zinc sulfide (ZnS:Cu) is the most common phosphor used and yields blue-green light. Copper and magnesium doped zinc sulfide (ZnS:Cu,Mg) yields yellow-orange light.

Tritium is also used as a source of radiation in various products utilizing tritium illumination.

Electroluminescence edit

Electroluminescence can be exploited in light sources. Such sources typically emit from a large area, which makes them suitable for backlights of LCD displays. The excitation of the phosphor is usually achieved by application of high-intensity electric field, usually with suitable frequency. Current electroluminescent light sources tend to degrade with use, resulting in their relatively short operation lifetimes.

ZnS:Cu was the first formulation successfully displaying electroluminescence, tested at 1936 by Georges Destriau in Madame Marie Curie laboratories in Paris.

Powder or AC electroluminescence is found in a variety of backlight and night light applications. Several groups offer branded EL offerings (e.g. IndiGlo used in some Timex watches) or "Lighttape", another trade name of an electroluminescent material, used in electroluminescent light strips. The Apollo space program is often credited with being the first significant use of EL for backlights and lighting.[21]

White LEDs edit

White light-emitting diodes are usually blue InGaN LEDs with a coating of a suitable material. Cerium(III)-doped YAG (YAG:Ce3+, or Y3Al5O12:Ce3+) is often used; it absorbs the light from the blue LED and emits in a broad range from greenish to reddish, with most of its output in yellow. This yellow emission combined with the remaining blue emission gives the "white" light, which can be adjusted to color temperature as warm (yellowish) or cold (bluish) white. The pale yellow emission of the Ce3+:YAG can be tuned by substituting the cerium with other rare-earth elements such as terbium and gadolinium and can even be further adjusted by substituting some or all of the aluminium in the YAG with gallium. However, this process is not one of phosphorescence. The yellow light is produced by a process known as scintillation, the complete absence of an afterglow being one of the characteristics of the process.

Some rare-earth-doped Sialons are photoluminescent and can serve as phosphors. Europium(II)-doped β-SiAlON absorbs in ultraviolet and visible light spectrum and emits intense broadband visible emission. Its luminance and color does not change significantly with temperature, due to the temperature-stable crystal structure. It has a great potential as a green down-conversion phosphor for white LEDs; a yellow variant also exists (α-SiAlON[22]). For white LEDs, a blue LED is used with a yellow phosphor, or with a green and yellow SiAlON phosphor and a red CaAlSiN3-based (CASN) phosphor.[23][24][25]

White LEDs can also be made by coating near-ultraviolet-emitting LEDs with a mixture of high-efficiency europium-based red- and blue-emitting phosphors plus green-emitting copper- and aluminium-doped zinc sulfide (ZnS:Cu,Al). This is a method analogous to the way fluorescent lamps work.

Some newer white LEDs use a yellow and blue emitter in series, to approximate white; this technology is used in some Motorola phones such as the Blackberry as well as LED lighting and the original-version stacked emitters by using GaN on SiC on InGaP but was later found to fracture at higher drive currents.

Many white LEDs used in general lighting systems can be used for data transfer, as, for example, in systems that modulate the LED to act as a beacon.[26]

It is also common for white LEDs to use phosphors other than Ce:YAG, or to use two or three phosphors to achieve a higher CRI, often at the cost of efficiency. Examples of additional phosphors are R9, which produces a saturated red, nitrides which produce red, and aluminates such as lutetium aluminum garnet that produce green. Silicate phosphors are brighter but fade more quickly, and are used in LCD LED backlights in mobile devices. LED phosphors can be placed directly over the die or made into a dome and placed above the LED: this approach is known as a remote phosphor.[27] Some colored LEDs, instead of using a colored LED, use a blue LED with a colored phosphor because such an arrangement is more efficient than a colored LED. Oxynitride phosphors can also be used in LEDs. The precursors used to make the phosphors may degrade when exposed to air.[28]

Cathode-ray tubes edit

 
Spectra of constituent blue, green and red phosphors in a common cathode-ray tube

Cathode-ray tubes produce signal-generated light patterns in a (typically) round or rectangular format. Bulky CRTs were used in the black-and-white household television (TV) sets that became popular in the 1950s, as well as first-generation, tube-based color TVs, and most earlier computer monitors. CRTs have also been widely used in scientific and engineering instrumentation, such as oscilloscopes, usually with a single phosphor color, typically green. Phosphors for such applications may have long afterglow, for increased image persistence.

The phosphors can be deposited as either thin film, or as discrete particles, a powder bound to the surface. Thin films have better lifetime and better resolution, but provide less bright and less efficient image than powder ones. This is caused by multiple internal reflections in the thin film, scattering the emitted light.

White (in black-and-white): The mix of zinc cadmium sulfide and zinc sulfide silver, the ZnS:Ag + (Zn,Cd)S:Ag is the white P4 phosphor used in black and white television CRTs. Mixes of yellow and blue phosphors are usual. Mixes of red, green and blue, or a single white phosphor, can also be encountered.

Red: Yttrium oxide-sulfide activated with europium is used as the red phosphor in color CRTs. The development of color TV took a long time due to the search for a red phosphor. The first red emitting rare-earth phosphor, YVO4:Eu3+, was introduced by Levine and Palilla as a primary color in television in 1964.[29] In single crystal form, it was used as an excellent polarizer and laser material.[30]

Yellow: When mixed with cadmium sulfide, the resulting zinc cadmium sulfide (Zn,Cd)S:Ag, provides strong yellow light.

Green: Combination of zinc sulfide with copper, the P31 phosphor or ZnS:Cu, provides green light peaking at 531 nm, with long glow.

Blue: Combination of zinc sulfide with few ppm of silver, the ZnS:Ag, when excited by electrons, provides strong blue glow with maximum at 450 nm, with short afterglow with 200 nanosecond duration. It is known as the P22B phosphor. This material, zinc sulfide silver, is still one of the most efficient phosphors in cathode-ray tubes. It is used as a blue phosphor in color CRTs.

The phosphors are usually poor electrical conductors. This may lead to deposition of residual charge on the screen, effectively decreasing the energy of the impacting electrons due to electrostatic repulsion (an effect known as "sticking"). To eliminate this, a thin layer of aluminium (about 100 nm) is deposited over the phosphors, usually by vacuum evaporation, and connected to the conductive layer inside the tube. This layer also reflects the phosphor light to the desired direction, and protects the phosphor from ion bombardment resulting from an imperfect vacuum.

To reduce the image degradation by reflection of ambient light, contrast can be increased by several methods. In addition to black masking of unused areas of screen, the phosphor particles in color screens are coated with pigments of matching color. For example, the red phosphors are coated with ferric oxide (replacing earlier Cd(S,Se) due to cadmium toxicity), blue phosphors can be coated with marine blue (CoO·nAl
2
O
3
) or ultramarine (Na
8
Al
6
Si
6
O
24
S
2
). Green phosphors based on ZnS:Cu do not have to be coated due to their own yellowish color.[7]

Black-and-white television CRTs edit

The black-and-white television screens require an emission color close to white. Usually, a combination of phosphors is employed.

The most common combination is ZnS:Ag + (Zn,Cd)S:Cu,Al (blue + yellow). Other ones are ZnS:Ag + (Zn,Cd)S:Ag (blue + yellow), and ZnS:Ag + ZnS:Cu,Al + Y2O2S:Eu3+ (blue + green + red – does not contain cadmium and has poor efficiency). The color tone can be adjusted by the ratios of the components.

As the compositions contain discrete grains of different phosphors, they produce image that may not be entirely smooth. A single, white-emitting phosphor, (Zn,Cd)S:Ag,Au,Al overcomes this obstacle. Due to its low efficiency, it is used only on very small screens.

The screens are typically covered with phosphor using sedimentation coating, where particles suspended in a solution are let to settle on the surface.[31]

Reduced-palette color CRTs edit

For displaying of a limited palette of colors, there are a few options.

In beam penetration tubes, different color phosphors are layered and separated with dielectric material. The acceleration voltage is used to determine the energy of the electrons; lower-energy ones are absorbed in the top layer of the phosphor, while some of the higher-energy ones shoot through and are absorbed in the lower layer. So either the first color or a mixture of the first and second color is shown. With a display with red outer layer and green inner layer, the manipulation of accelerating voltage can produce a continuum of colors from red through orange and yellow to green.

Another method is using a mixture of two phosphors with different characteristics. The brightness of one is linearly dependent on electron flux, while the other one's brightness saturates at higher fluxes—the phosphor does not emit any more light regardless of how many more electrons impact it. At low electron flux, both phosphors emit together; at higher fluxes, the luminous contribution of the nonsaturating phosphor prevails, changing the combined color.[31]

Such displays can have high resolution, due to absence of two-dimensional structuring of RGB CRT phosphors. Their color palette is, however, very limited. They were used e.g. in some older military radar displays.

Color television CRTs edit

The phosphors in color CRTs need higher contrast and resolution than the black-and-white ones. The energy density of the electron beam is about 100 times greater than in black-and-white CRTs; the electron spot is focused to about 0.2 mm diameter instead of about 0.6 mm diameter of the black-and-white CRTs. Effects related to electron irradiation degradation are therefore more pronounced.

Color CRTs require three different phosphors, emitting in red, green and blue, patterned on the screen. Three separate electron guns are used for color production (except for displays that use beam-index tube technology, which is rare). The red phosphor has always been a problem, being the dimmest of the three necessitating the brighter green and blue electron beam currents be adjusted down to make them equal the red phosphor's lower brightness. This made early color TVs only usable indoors as bright light made it impossible to see the dim picture, while portable black-and-white TVs viewable in outdoor sunlight were already common.

The composition of the phosphors changed over time, as better phosphors were developed and as environmental concerns led to lowering the content of cadmium and later abandoning it entirely. The (Zn,Cd)S:Ag,Cl was replaced with (Zn,Cd)S:Cu,Al with lower cadmium/zinc ratio, and then with cadmium-free ZnS:Cu,Al.

The blue phosphor stayed generally unchanged, a silver-doped zinc sulfide. The green phosphor initially used manganese-doped zinc silicate, then evolved through silver-activated cadmium-zinc sulfide, to lower-cadmium copper-aluminium activated formula, and then to cadmium-free version of the same. The red phosphor saw the most changes; it was originally manganese-activated zinc phosphate, then a silver-activated cadmium-zinc sulfide, then the europium(III) activated phosphors appeared; first in an yttrium vanadate matrix, then in yttrium oxide and currently in yttrium oxysulfide. The evolution of the phosphors was therefore (ordered by B-G-R):

  • ZnS:Ag – Zn2SiO4:Mn – Zn3(PO4)2:Mn
  • ZnS:Ag – (Zn,Cd)S:Ag – (Zn,Cd)S:Ag
  • ZnS:Ag – (Zn,Cd)S:Ag – YVO4:Eu3+ (1964–?)
  • ZnS:Ag – (Zn,Cd)S:Cu,Al – Y2O2S:Eu3+ or Y2O3:Eu3+
  • ZnS:Ag – ZnS:Cu,Al or ZnS:Au,Cu,Al – Y2O2S:Eu3+[31]

Projection televisions edit

For projection televisions, where the beam power density can be two orders of magnitude higher than in conventional CRTs, some different phosphors have to be used.

For blue color, ZnS:Ag,Cl is employed. However, it saturates. (La,Gd)OBr:Ce,Tb3+ can be used as an alternative that is more linear at high energy densities.

For green, a terbium-activated Gd2O2Tb3+; its color purity and brightness at low excitation densities is worse than the zinc sulfide alternative, but it behaves linear at high excitation energy densities, while zinc sulfide saturates. However, it also saturates, so Y3Al5O12:Tb3+ or Y2SiO5:Tb3+ can be substituted. LaOBr:Tb3+ is bright but water-sensitive, degradation-prone, and the plate-like morphology of its crystals hampers its use; these problems are solved now, so it is gaining use due to its higher linearity.

Y2O2S:Eu3+ is used for red emission.[31]

Standard phosphor types edit

Standard phosphor types[32][33]
Phosphor Composition Color Wavelength Peak width Persistence Usage Notes
P1, GJ Zn2SiO4:Mn (Willemite) Green 525 nm 40 nm[34] 1-100ms CRT, Lamp Oscilloscopes and monochrome monitors
P2 ZnS:Cu(Ag)(B*) Blue-Green 543 nm Long CRT Oscilloscopes
P3 Zn8:BeSi5O19:Mn Yellow 602 nm Medium/13 ms CRT Amber monochrome monitors
P4 ZnS:Ag+(Zn,Cd)S:Ag White 565,540 nm Short CRT Black and white TV CRTs and display tubes.
P4 (Cd-free) ZnS:Ag+ZnS:Cu+Y2O2S:Eu White Short CRT Black and white TV CRTs and display tubes, Cd free.
P5 CaWO4:W Blue 430 nm Very Short CRT Film
P6 ZnS:Ag+ZnS:CdS:Ag White 565,460 nm Short CRT
P7 (Zn,Cd)S:Cu Blue with Yellow persistence 558,440 nm Long CRT Radar PPI, old EKG monitors, early oscilloscopes
P10 KCl green-absorbing scotophor Long Dark-trace CRTs Radar screens; turns from translucent white to dark magenta, stays changed until erased by heating or infrared light
P11, BE ZnS:Ag,Cl or ZnS:Zn Blue 460 nm 0.01-1 ms CRT, VFD Display tubes and VFDs; Oscilloscopes (for fast photographic recording)[35]
P12 Zn(Mg)F2:Mn Orange 590 nm Medium/long CRT Radar
P13 MgSi2O6:Mn Reddish Orange-Reddish Orange 640 nm Medium CRT Flying spot scanning systems and photographic applications
P14 ZnS:Ag on ZnS:CdS:Cu Blue with Orange persistence Medium/long CRT Radar PPI, old EKG monitors
P15 ZnO:Zn Blue-Green 504,391 nm Extremely Short CRT Television pickup by flying-spot scanning
P16 CaMgSi2O6:Ce Bluish Purple-Bluish Purple 380 nm Very Short CRT Flying spot scanning systems and photographic applications
P17 ZnO,ZnCdS:Cu Blue-Yellow 504,391 nm Blue-Short, Yellow-Long CRT
P18 CaMgSi2O6:Ti, BeSi2O6:Mn white-white 545,405 nm Medium to Short CRT
P19, LF (KF,MgF2):Mn Orange-Yellow 590 nm Long CRT Radar screens
P20, KA (Zn,Cd)S:Ag or (Zn,Cd)S:Cu Yellow-green 555 nm 1–100 ms CRT Display tubes
P21 MgF2:Mn2+ Reddish 605 nm CRT, Radar Registered by Allen B DuMont Laboratories
P22R Y2O2S:Eu+Fe2O3 Red 611 nm Short CRT Red phosphor for TV screens
P22G ZnS:Cu,Al Green 530 nm Short CRT Green phosphor for TV screens
P22B ZnS:Ag+Co-on-Al2O3 Blue Short CRT Blue phosphor for TV screens
P23 ZnS:Ag+(Zn,Cd)S:Ag White 575,460 nm Short CRT, Direct viewing television Registered by United States Radium Corporation.
P24, GE ZnO:Zn Green 505 nm 1–10 μs VFD most common phosphor in vacuum fluorescent displays.[36]
P25 CaSi2O6:Pb:Mn Orange-Orange 610 nm Medium CRT Military Displays - 7UP25 CRT
P26, LC (KF,MgF2):Mn Orange 595 nm Long CRT Radar screens
P27 ZnPO4:Mn Reddish Orange-Reddish Orange 635 nm Medium CRT Color TV monitor service
P28, KE (Zn,Cd)S:Cu,Cl Yellow Medium CRT Display tubes
P29 Alternating P2 and P25 stripes Blue-Green/Orange stripes Medium CRT Radar screens
P31, GH ZnS:Cu or ZnS:Cu,Ag Yellowish-green 0.01-1 ms CRT Oscilloscopes and monochrome monitors
P33, LD MgF2:Mn Orange 590 nm > 1sec CRT Radar screens
P34 Bluish Green-Yellow Green Very Long CRT
P35 ZnS,ZnSe:Ag Blue White-Blue White 455 nm Medium Short CRT Photographic registration on orthochromatic film materials
P38, LK (Zn,Mg)F2:Mn Orange-Yellow 590 nm Long CRT Radar screens
P39, GR Zn2SiO4:Mn,As Green 525 nm Long CRT Display tubes
P40, GA ZnS:Ag+(Zn,Cd)S:Cu White Long CRT Display tubes
P43, GY Gd2O2S:Tb Yellow-green 545 nm Medium CRT Display tubes, Electronic Portal Imaging Devices (EPIDs) used in radiation therapy linear accelerators for cancer treatment
P45, WB Y2O2S:Tb White 545 nm Short CRT Viewfinders
P46, KG Y3Al5O12:Ce Green 530 nm Very short (70ns) CRT Beam-index tube
P47, BH Y2SiO5:Ce Blue 400 nm Very short CRT Beam-index tube
P53, KJ Y3Al5O12:Tb Yellow-green 544 nm Short CRT Projection tubes
P55, BM ZnS:Ag,Al Blue 450 nm Short CRT Projection tubes
ZnS:Ag Blue 450 nm CRT
ZnS:Cu,Al or ZnS:Cu,Au,Al Green 530 nm CRT
(Zn,Cd)S:Cu,Cl+(Zn,Cd)S:Ag,Cl White CRT
Y2SiO5:Tb Green 545 nm CRT Projection tubes
Y2OS:Tb Green 545 nm CRT Display tubes
Y3(Al,Ga)5O12:Ce Green 520 nm Short CRT Beam-index tube
Y3(Al,Ga)5O12:Tb Yellow-green 544 nm Short CRT Projection tubes
InBO3:Tb Yellow-green 550 nm CRT
InBO3:Eu Yellow 588 nm CRT
InBO3:Tb+InBO3:Eu amber CRT Computer displays
InBO3:Tb+InBO3:Eu+ZnS:Ag White CRT
(Ba,Eu)Mg2Al16O27 Blue Lamp Trichromatic fluorescent lamps
(Ce,Tb)MgAl11O19 Green 546 nm 9 nm Lamp Trichromatic fluorescent lamps[34]
BAM BaMgAl10O17:Eu,Mn Blue 450 nm Lamp, displays Trichromatic fluorescent lamps
BaMg2Al16O27:Eu(II) Blue 450 nm 52 nm Lamp Trichromatic fluorescent lamps[34]
BAM BaMgAl10O17:Eu,Mn Blue-Green 456 nm,514 nm Lamp
BaMg2Al16O27:Eu(II),Mn(II) Blue-Green 456 nm, 514 nm 50 nm 50%[34] Lamp
Ce0.67Tb0.33MgAl11O19:Ce,Tb Green 543 nm Lamp Trichromatic fluorescent lamps
Zn2SiO4:Mn,Sb2O3 Green 528 nm Lamp
CaSiO3:Pb,Mn Orange-Pink 615 nm 83 nm[34] Lamp
CaWO4 (Scheelite) Blue 417 nm Lamp
CaWO4:Pb Blue 433 nm/466 nm 111 nm Lamp Wide bandwidth[34]
MgWO4 Blue pale 473 nm 118 nm Lamp Wide bandwidth, deluxe blend component [34]
(Sr,Eu,Ba,Ca)5(PO4)3Cl Blue Lamp Trichromatic fluorescent lamps
Sr5Cl(PO4)3:Eu(II) Blue 447 nm 32 nm[34] Lamp
(Ca,Sr,Ba)3(PO4)2Cl2:Eu Blue 452 nm Lamp
(Sr,Ca,Ba)10(PO4)6Cl2:Eu Blue 453 nm Lamp Trichromatic fluorescent lamps
Sr2P2O7:Sn(II) Blue 460 nm 98 nm Lamp Wide bandwidth, deluxe blend component[34]
Sr6P5BO20:Eu Blue-Green 480 nm 82 nm[34] Lamp
Ca5F(PO4)3:Sb Blue 482 nm 117 nm Lamp Wide bandwidth[34]
(Ba,Ti)2P2O7:Ti Blue-Green 494 nm 143 nm Lamp Wide bandwidth, deluxe blend component [34]
3Sr3(PO4)2.SrF2:Sb,Mn Blue 502 nm Lamp
Sr5F(PO4)3:Sb,Mn Blue-Green 509 nm 127 nm Lamp Wide bandwidth[34]
Sr5F(PO4)3:Sb,Mn Blue-Green 509 nm 127 nm Lamp Wide bandwidth[34]
LaPO4:Ce,Tb Green 544 nm Lamp Trichromatic fluorescent lamps
(La,Ce,Tb)PO4 Green Lamp Trichromatic fluorescent lamps
(La,Ce,Tb)PO4:Ce,Tb Green 546 nm 6 nm Lamp Trichromatic fluorescent lamps[34]
Ca3(PO4)2.CaF2:Ce,Mn Yellow 568 nm Lamp
(Ca,Zn,Mg)3(PO4)2:Sn Orange-pink 610 nm 146 nm Lamp Wide bandwidth, blend component[34]
(Zn,Sr)3(PO4)2:Mn Orange-Red 625 nm Lamp
(Sr,Mg)3(PO4)2:Sn Orange-pinkish white 626 nm 120 nm Fluorescent lamps Wide bandwidth, deluxe blend component[34]
(Sr,Mg)3(PO4)2:Sn(II) Orange-red 630 nm Fluorescent lamps
Ca5F(PO4)3:Sb,Mn 3800K Fluorescent lamps Lite-white blend[34]
Ca5(F,Cl)(PO4)3:Sb,Mn White-Cold/Warm Fluorescent lamps 2600 to 9900 K, for very high output lamps[34]
(Y,Eu)2O3 Red Lamp Trichromatic fluorescent lamps
Y2O3:Eu(III) Red 611 nm 4 nm Lamp Trichromatic fluorescent lamps[34]
Mg4(F)GeO6:Mn Red 658 nm 17 nm High-pressure mercury lamps [34]
Mg4(F)(Ge,Sn)O6:Mn Red 658 nm Lamp
Y(P,V)O4:Eu Orange-Red 619 nm Lamp
YVO4:Eu Orange-Red 619 nm High Pressure Mercury and Metal Halide Lamps
Y2O2S:Eu Red 626 nm Lamp
3.5 MgO · 0.5 MgF2 · GeO2 :Mn Red 655 nm Lamp 3.5 MgO · 0.5 MgF2 · GeO2 :Mn
Mg5As2O11:Mn Red 660 nm High-pressure mercury lamps, 1960s
SrAl2O7:Pb Ultraviolet 313 nm Special fluorescent lamps for medical use Ultraviolet
CAM LaMgAl11O19:Ce Ultraviolet 340 nm 52 nm Black-light fluorescent lamps Ultraviolet
LAP LaPO4:Ce Ultraviolet 320 nm 38 nm Medical and scientific UV lamps Ultraviolet
SAC SrAl12O19:Ce Ultraviolet 295 nm 34 nm Lamp Ultraviolet
SrAl11Si0.75O19:Ce0.15Mn0.15 Green 515 nm 22 nm Lamp Monochromatic lamps for copiers[37]
BSP BaSi2O5:Pb Ultraviolet 350 nm 40 nm Lamp Ultraviolet
SrFB2O3:Eu(II) Ultraviolet 366 nm Lamp Ultraviolet
SBE SrB4O7:Eu Ultraviolet 368 nm 15 nm Lamp Ultraviolet
SMS Sr2MgSi2O7:Pb Ultraviolet 365 nm 68 nm Lamp Ultraviolet
MgGa2O4:Mn(II) Blue-Green Lamp Black light displays

Various edit

Some other phosphors commercially available, for use as X-ray screens, neutron detectors, alpha particle scintillators, etc., are:

  • Gd2O2S:Tb (P43), green (peak at 545 nm), 1.5 ms decay to 10%, low afterglow, high X-ray absorption, for X-ray, neutrons and gamma
  • Gd2O2S:Eu, red (627 nm), 850 μs decay, afterglow, high X-ray absorption, for X-ray, neutrons and gamma
  • Gd2O2S:Pr, green (513 nm), 7 μs decay, no afterglow, high X-ray absorption, for X-ray, neutrons and gamma
  • Gd2O2S:Pr,Ce,F, green (513 nm), 4 μs decay, no afterglow, high X-ray absorption, for X-ray, neutrons and gamma
  • Y2O2S:Tb (P45), white (545 nm), 1.5 ms decay, low afterglow, for low-energy X-ray
  • Y2O2S:Eu (P22R), red (627 nm), 850 μs decay, afterglow, for low-energy X-ray
  • Y2O2S:Pr, white (513 nm), 7 μs decay, no afterglow, for low-energy X-ray
  • Zn
    0.5
    Cd
    0.4
    S:Ag
    (HS), green (560 nm), 80 μs decay, afterglow, efficient but low-res X-ray
  • Zn
    0.4
    Cd
    0.6
    S:Ag
    (HSr), red (630 nm), 80 μs decay, afterglow, efficient but low-res X-ray
  • CdWO4, blue (475 nm), 28 μs decay, no afterglow, intensifying phosphor for X-ray and gamma
  • CaWO4, blue (410 nm), 20 μs decay, no afterglow, intensifying phosphor for X-ray
  • MgWO4, white (500 nm), 80 μs decay, no afterglow, intensifying phosphor
  • Y2SiO5:Ce (P47), blue (400 nm), 120 ns decay, no afterglow, for electrons, suitable for photomultipliers
  • YAlO3:Ce (YAP), blue (370 nm), 25 ns decay, no afterglow, for electrons, suitable for photomultipliers
  • Y3Al5O12:Ce (YAG), green (550 nm), 70 ns decay, no afterglow, for electrons, suitable for photomultipliers
  • Y3(Al,Ga)5O12:Ce (YGG), green (530 nm), 250 ns decay, low afterglow, for electrons, suitable for photomultipliers
  • CdS:In, green (525 nm), <1 ns decay, no afterglow, ultrafast, for electrons
  • ZnO:Ga, blue (390 nm), <5 ns decay, no afterglow, ultrafast, for electrons
  • ZnO:Zn (P15), blue (495 nm), 8 μs decay, no afterglow, for low-energy electrons
  • (Zn,Cd)S:Cu,Al (P22G), green (565 nm), 35 μs decay, low afterglow, for electrons
  • ZnS:Cu,Al,Au (P22G), green (540 nm), 35 μs decay, low afterglow, for electrons
  • ZnCdS:Ag,Cu (P20), green (530 nm), 80 μs decay, low afterglow, for electrons
  • ZnS:Ag (P11), blue (455 nm), 80 μs decay, low afterglow, for alpha particles and electrons
  • anthracene, blue (447 nm), 32 ns decay, no afterglow, for alpha particles and electrons
  • plastic (EJ-212), blue (400 nm), 2.4 ns decay, no afterglow, for alpha particles and electrons
  • Zn2SiO4:Mn (P1), green (530 nm), 11 ms decay, low afterglow, for electrons
  • ZnS:Cu (GS), green (520 nm), decay in minutes, long afterglow, for X-rays
  • NaI:Tl, for X-ray, alpha, and electrons
  • CsI:Tl, green (545 nm), 5 μs decay, afterglow, for X-ray, alpha, and electrons
  • 6LiF/ZnS:Ag (ND), blue (455 nm), 80 μs decay, for thermal neutrons
  • 6LiF/ZnS:Cu,Al,Au (NDg), green (565 nm), 35 μs decay, for neutrons
  • Cerium doped YAG phosphor, yellow, used in white LEDs for turning blue to white light with a broad spectrum of light

See also edit

References edit

  1. ^ Emsley, John (2000). The Shocking History of Phosphorus. London: Macmillan. ISBN 978-0-330-39005-7.
  2. ^ Xie, Rong-Jun; Hirosaki, Naoto (2007). "Silicon-based oxynitride and nitride phosphors for white LEDs—A review". Sci. Technol. Adv. Mater. 8 (7–8): 588. Bibcode:2007STAdM...8..588X. doi:10.1016/j.stam.2007.08.005. 
  3. ^ Li, Hui-Li; Hirosaki, Naoto; Xie, Rong-Jun; Suehiro, Takayuki; Mitomo, Mamoru (2007). "Fine yellow α-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method". Sci. Technol. Adv. Mater. 8 (7–8): 601. Bibcode:2007STAdM...8..601L. doi:10.1016/j.stam.2007.09.003. 
  4. ^ Kane, Raymond and Sell, Heinz (2001) Revolution in lamps: a chronicle of 50 years of progress, 2nd ed. The Fairmont Press. ISBN 0-88173-378-4. Chapter 5 extensively discusses history, application and manufacturing of phosphors for lamps.
  5. ^ a b Matsuzawa, T.; Aoki, Y.; Takeuchi, N.; Murayama, Y. (1996-08-01). "A New Long Phosphorescent Phosphor with High Brightness, SrAl2O4: Eu2+, Dy3+". Journal of the Electrochemical Society. 143 (8): 2670–2673. Bibcode:1996JElS..143.2670M. doi:10.1149/1.1837067. ISSN 0013-4651.
  6. ^ US5424006A, "Phosphorescent phosphor", issued 1994-02-25 
  7. ^ a b c d e f g Peter W. Hawkes (1 October 1990). Advances in electronics and electron physics. Academic Press. pp. 350–. ISBN 978-0-12-014679-6. Retrieved 9 January 2012.
  8. ^ Bizarri, G; Moine, B (2005). "On phosphor degradation mechanism: thermal treatment effects". Journal of Luminescence. 113 (3–4): 199. Bibcode:2005JLum..113..199B. doi:10.1016/j.jlumin.2004.09.119.
  9. ^ Lakshmanan, p. 171.
  10. ^ Tanno, Hiroaki; Fukasawa, Takayuki; Zhang, Shuxiu; Shinoda, Tsutae; Kajiyama, Hiroshi (2009). "Lifetime Improvement of BaMgAl10O17:Eu2+ Phosphor by Hydrogen Plasma Treatment". Japanese Journal of Applied Physics. 48 (9): 092303. Bibcode:2009JaJAP..48i2303T. doi:10.1143/JJAP.48.092303. S2CID 94464554.
  11. ^ Ntwaeaborwa, O. M.; Hillie, K. T.; Swart, H. C. (2004). "Degradation of Y2O3:Eu phosphor powders". Physica Status Solidi C. 1 (9): 2366. Bibcode:2004PSSCR...1.2366N. doi:10.1002/pssc.200404813.
  12. ^ Wang, Ching-Wu; Sheu, Tong-Ji; Su, Yan-Kuin; Yokoyama, Meiso (1997). "Deep Traps and Mechanism of Brightness Degradation in Mn-doped ZnS Thin-Film Electroluminescent Devices Grown by Metal-Organic Chemical Vapor Deposition". Japanese Journal of Applied Physics. 36 (5A): 2728. Bibcode:1997JaJAP..36.2728W. doi:10.1143/JJAP.36.2728. S2CID 98131548.
  13. ^ Lakshmanan, pp. 51, 76
  14. ^ . Tubedevices.com. Archived from the original on 2013-12-28. Retrieved 2016-12-15.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  15. ^ "Vacuum light sources — High speed stroboscopic light sources data sheet" (PDF). Ferranti, Ltd. August 1958. (PDF) from the original on 20 September 2016. Retrieved 7 May 2017.
  16. ^ Lehner, P.; Staudinger, C.; Borisov, S. M.; Klimant, l. (2014). "Ultra-sensitive optical oxygen sensors for characterization of nearly anoxic systems". Nature Communications. 5: 4460. Bibcode:2014NatCo...5.4460L. doi:10.1038/ncomms5460. PMC 4109599. PMID 25042041.
  17. ^ Hamzehpoor, E; Ruchlin, C.; Tao, Y.; Liu, C. H.; Titi, H. M.; Perepichka, D. F. (2022). "Efficient room-temperature phosphorescence of covalent organic frameworks through covalent halogen doping". Nature Chemistry. 15 (1): 83–90. doi:10.1038/s41557-022-01070-4. PMID 36302870. S2CID 253183290.
  18. ^ Xie, Z.; Ma, L.; deKrafft, K. E.; Jin, A.; Lin, W. (2010). "Porous phosphorescent coordination polymers for oxygen sensing". J. Am. Chem. Soc. 132 (3): 922–923. doi:10.1021/ja909629f. PMID 20041656.
  19. ^ SEEING PHOSPHOR BANDS on U.K. STAMPS 2015-10-19 at the Wayback Machine.
  20. ^ Phosphor Bands 2017-03-17 at the Wayback Machine.
  21. ^ "Archived copy" (PDF). (PDF) from the original on 2016-12-21. Retrieved 2017-02-12.{{cite web}}: CS1 maint: archived copy as title (link)
  22. ^ XTECH, NIKKEI. "Sharp to Employ White LED Using Sialon". NIKKEI XTECH. Retrieved 2019-01-10.
  23. ^ Youn-Gon Park; et al. . Samsung Electro Mechanics Co. Archived from the original on 2010-04-12. Retrieved 2009-09-24.
  24. ^ Hideyoshi Kume, Nikkei Electronics (Sep 15, 2009). "Sharp to Employ White LED Using Sialon". from the original on 2012-02-23.
  25. ^ Naoto, Hirosaki; et al. (2005). . Oyo Butsuri. 74 (11): 1449. Archived from the original on 2010-04-04.
  26. ^ Fudin, M.S.; et al. (2014). "Frequency characteristics of modern LED phosphor materials". Scientific and Technical Journal of Information Technologies, Mechanics and Optics. 14 (6): 71. from the original on 2015-06-26.
  27. ^ Bush, Steve (March 14, 2014). "Discussing LED lighting phosphors".
  28. ^ Setlur, Anant A. (1 December 2009). "Phosphors for LED-based Solid-State Lighting" (PDF). The Electrochemical Society Interface. 18 (4): 32–36. doi:10.1149/2.F04094IF. Retrieved 5 December 2022.
  29. ^ Levine, Albert K.; Palilla, Frank C. (1964). "A new, highly efficient red-emitting cathodoluminescent phosphor (YVO4:Eu) for color television". Applied Physics Letters. 5 (6): 118. Bibcode:1964ApPhL...5..118L. doi:10.1063/1.1723611.
  30. ^ Fields, R. A.; Birnbaum, M.; Fincher, C. L. (1987). "Highly efficient Nd:YVO4 diode-laser end-pumped laser". Applied Physics Letters. 51 (23): 1885. Bibcode:1987ApPhL..51.1885F. doi:10.1063/1.98500.
  31. ^ a b c d Lakshmanan, p. 54.
  32. ^ Shionoya, Shigeo (1999). "VI: Phosphors for cathode ray tubes". Phosphor handbook. Boca Raton, Fla.: CRC Press. ISBN 978-0-8493-7560-6.
  33. ^ Jankowiak, Patrick. "Cathode Ray Tube Phosphors" (PDF). bunkerofdoom.com. (PDF) from the original on 19 January 2013. Retrieved 1 May 2012.[unreliable source?]
  34. ^ a b c d e f g h i j k l m n o p q r s t u . Archived from the original on July 24, 2011. Retrieved 2009-06-06.
  35. ^ Keller, Peter (1991). The Cathode-Ray Tube: Technology, History, and Applications. Palisades Press. p. 17. ISBN 0963155903.
  36. ^ "VFD|Futaba Corporation". 27 February 2021.
  37. ^ Lagos C (1974) "Strontium aluminate phosphor activated by cerium and manganese" U.S. patent 3,836,477

Bibliography edit

  • Arunachalam Lakshmanan (2008). Luminescence and Display Phosphors: Phenomena and Applications. Nova Publishers. ISBN 978-1-60456-018-3.

External links edit

  • a history of electroluminescent displays 2012-04-30 at the Wayback Machine.
  • Fluorescence, Phosphorescence
  • (P numbers)
  • Silicon-based oxynitride and nitride phosphors for white LEDs—A review
  • [1] 2023-04-10 at the Wayback Machine & [2] 2023-04-10 at the Wayback Machine – RCA Manual, Fluorescent screens (P1 to P24)
  • Inorganic Phosphors Compositions, Preparation and Optical Properties, William M. Yen and Marvin J. Weber 2016-03-06 at the Wayback Machine

phosphor, chemical, element, phosphorus, phosphor, substance, that, exhibits, phenomenon, luminescence, emits, light, when, exposed, some, type, radiant, energy, term, used, both, fluorescent, phosphorescent, substances, which, glow, exposure, ultraviolet, vis. For the chemical element see phosphorus A phosphor is a substance that exhibits the phenomenon of luminescence it emits light when exposed to some type of radiant energy The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light and cathodoluminescent substances which glow when struck by an electron beam cathode rays in a cathode ray tube Example of phosphorescenceMonochrome monitorAperture grille CRT phosphorsWhen a phosphor is exposed to radiation the orbital electrons in its molecules are excited to a higher energy level when they return to their former level they emit the energy as light of a certain color Phosphors can be classified into two categories fluorescent substances which emit the energy immediately and stop glowing when the exciting radiation is turned off and phosphorescent substances which emit the energy after a delay so they keep glowing after the radiation is turned off decaying in brightness over a period of milliseconds to days Fluorescent materials are used in applications in which the phosphor is excited continuously cathode ray tubes CRT and plasma video display screens fluoroscope screens fluorescent lights scintillation sensors white LEDs and luminous paints for black light art Phosphorescent materials are used where a persistent light is needed such as glow in the dark watch faces and aircraft instruments and in radar screens to allow the target blips to remain visible as the radar beam rotates CRT phosphors were standardized beginning around World War II and designated by the letter P followed by a number Phosphorus the light emitting chemical element for which phosphors are named emits light due to chemiluminescence not phosphorescence 1 Contents 1 Light emission process 2 Materials 3 Phosphor degradation 4 Applications 4 1 Lighting 4 2 Phosphor thermometry 4 3 Glow in the dark toys 4 4 Oxygen sensing 4 5 Postage stamps 4 6 Radioluminescence 4 7 Electroluminescence 4 8 White LEDs 4 9 Cathode ray tubes 4 9 1 Black and white television CRTs 4 9 2 Reduced palette color CRTs 4 9 3 Color television CRTs 4 9 4 Projection televisions 5 Standard phosphor types 5 1 Various 6 See also 7 References 8 Bibliography 9 External linksLight emission process edit nbsp Jablonski diagram shows the energy levels in a fluorescing atom in a phosphor An electron in the phosphor absorbs a high energy photon from the applied radiation exciting it to a higher energy level After losing some energy in non radiative transitions it eventually transitions back to its ground state energy level by fluorescence emitting a photon of lower energy in the visible light region The scintillation process in inorganic materials is due to the electronic band structure found in the crystals An incoming particle can excite an electron from the valence band to either the conduction band or the exciton band located just below the conduction band and separated from the valence band by an energy gap This leaves an associated hole behind in the valence band Impurities create electronic levels in the forbidden gap The excitons are loosely bound electron hole pairs that wander through the crystal lattice until they are captured as a whole by impurity centers The latter then rapidly de excite by emitting scintillation light fast component In the case of inorganic scintillators the activator impurities are typically chosen so that the emitted light is in the visible range or near UV where photomultipliers are effective The holes associated with electrons in the conduction band are independent from the latter Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons The delayed de excitation of those metastable impurity states slowed by reliance on the low probability forbidden mechanism again results in light emission slow component Phosphors are often transition metal compounds or rare earth compounds of various types In inorganic phosphors these inhomogeneities in the crystal structure are created usually by addition of a trace amount of dopants impurities called activators In rare cases dislocations or other crystal defects can play the role of the impurity The wavelength emitted by the emission center is dependent on the atom itself and on the surrounding crystal structure Materials editPhosphors are usually made from a suitable host material with an added activator The best known type is a copper activated zinc sulfide ZnS and the silver activated zinc sulfide zinc sulfide silver The host materials are typically oxides nitrides and oxynitrides 2 sulfides selenides halides or silicates of zinc cadmium manganese aluminium silicon or various rare earth metals The activators prolong the emission time afterglow In turn other materials such as nickel can be used to quench the afterglow and shorten the decay part of the phosphor emission characteristics Many phosphor powders are produced in low temperature processes such as sol gel and usually require post annealing at temperatures of 1000 C which is undesirable for many applications However proper optimization of the growth process allows manufacturers to avoid the annealing 3 Phosphors used for fluorescent lamps require a multi step production process with details that vary depending on the particular phosphor Bulk material must be milled to obtain a desired particle size range since large particles produce a poor quality lamp coating and small particles produce less light and degrade more quickly During the firing of the phosphor process conditions must be controlled to prevent oxidation of the phosphor activators or contamination from the process vessels After milling the phosphor may be washed to remove minor excess of activator elements Volatile elements must not be allowed to escape during processing Lamp manufacturers have changed compositions of phosphors to eliminate some toxic elements such as beryllium cadmium or thallium formerly used 4 The commonly quoted parameters for phosphors are the wavelength of emission maximum in nanometers or alternatively color temperature in kelvins for white blends the peak width in nanometers at 50 of intensity and decay time in seconds Examples Calcium sulfide with strontium sulfide with bismuth as activator Ca Sr S Bi yields blue light with glow times up to 12 hours red and orange are modifications of the zinc sulfide formula Red color can be obtained from strontium sulfide Zinc sulfide with about 5 ppm of a copper activator is the most common phosphor for the glow in the dark toys and items It is also called GS phosphor Mix of zinc sulfide and cadmium sulfide emit color depending on their ratio increasing of the CdS content shifts the output color towards longer wavelengths its persistence ranges between 1 10 hours Strontium aluminate activated by europium SrAl2O4 Eu II Dy III is a material developed in 1993 by Nemoto amp Co engineer Yasumitsu Aoki with higher brightness and significantly longer glow persistence it produces green and aqua hues where green gives the highest brightness and aqua the longest glow time 5 6 SrAl2O4 Eu Dy is about 10 times brighter 10 times longer glowing and 10 times more expensive than ZnS Cu 5 The excitation wavelengths for strontium aluminate range from 200 to 450 nm The wavelength for its green formulation is 520 nm its blue green version emits at 505 nm and the blue one emits at 490 nm Colors with longer wavelengths can be obtained from the strontium aluminate as well though for the price of some loss of brightness Phosphor degradation editMany phosphors tend to lose efficiency gradually by several mechanisms The activators can undergo change of valence usually oxidation the crystal lattice degrades atoms often the activators diffuse through the material the surface undergoes chemical reactions with the environment with consequent loss of efficiency or buildup of a layer absorbing either the exciting or the radiated energy etc The degradation of electroluminescent devices depends on frequency of driving current the luminance level and temperature moisture impairs phosphor lifetime very noticeably as well Harder high melting water insoluble materials display lower tendency to lose luminescence under operation 7 Examples BaMgAl10O17 Eu2 BAM a plasma display phosphor undergoes oxidation of the dopant during baking Three mechanisms are involved absorption of oxygen atoms into oxygen vacancies on the crystal surface diffusion of Eu II along the conductive layer and electron transfer from Eu II to absorbed oxygen atoms leading to formation of Eu III with corresponding loss of emissivity 8 Thin coating of aluminium phosphate or lanthanum III phosphate is effective in creating a barrier layer blocking access of oxygen to the BAM phosphor for the cost of reduction of phosphor efficiency 9 Addition of hydrogen acting as a reducing agent to argon in the plasma displays significantly extends the lifetime of BAM Eu2 phosphor by reducing the Eu III atoms back to Eu II 10 Y2O3 Eu phosphors under electron bombardment in presence of oxygen form a non phosphorescent layer on the surface where electron hole pairs recombine nonradiatively via surface states 11 ZnS Mn used in AC thin film electroluminescent ACTFEL devices degrades mainly due to formation of deep level traps by reaction of water molecules with the dopant the traps act as centers for nonradiative recombination The traps also damage the crystal lattice Phosphor aging leads to decreased brightness and elevated threshold voltage 12 ZnS based phosphors in CRTs and FEDs degrade by surface excitation coulombic damage build up of electric charge and thermal quenching Electron stimulated reactions of the surface are directly correlated to loss of brightness The electrons dissociate impurities in the environment the reactive oxygen species then attack the surface and form carbon monoxide and carbon dioxide with traces of carbon and nonradiative zinc oxide and zinc sulfate on the surface the reactive hydrogen removes sulfur from the surface as hydrogen sulfide forming nonradiative layer of metallic zinc Sulfur can be also removed as sulfur oxides 13 ZnS and CdS phosphors degrade by reduction of the metal ions by captured electrons The M2 ions are reduced to M two M then exchange an electron and become one M2 and one neutral M atom The reduced metal can be observed as a visible darkening of the phosphor layer The darkening and the brightness loss is proportional to the phosphor s exposure to electrons and can be observed on some CRT screens that displayed the same image e g a terminal login screen for prolonged periods 14 Europium II doped alkaline earth aluminates degrade by formation of color centers 7 Y2 SiO5 Ce3 degrades by loss of luminescent Ce3 ions 7 Zn2 SiO4 Mn P1 degrades by desorption of oxygen under electron bombardment 7 Oxide phosphors can degrade rapidly in presence of fluoride ions remaining from incomplete removal of flux from phosphor synthesis 7 Loosely packed phosphors e g when an excess of silica gel formed from the potassium silicate binder is present have tendency to locally overheat due to poor thermal conductivity E g InBO3 Tb3 is subject to accelerated degradation at higher temperatures 7 Applications editLighting edit Phosphor layers provide most of the light produced by fluorescent lamps and are also used to improve the balance of light produced by metal halide lamps Various neon signs use phosphor layers to produce different colors of light Electroluminescent displays found for example in aircraft instrument panels use a phosphor layer to produce glare free illumination or as numeric and graphic display devices White LED lamps consist of a blue or ultra violet emitter with a phosphor coating that emits at longer wavelengths giving a full spectrum of visible light Unfocused and undeflected cathode ray tubes have been used as stroboscope lamps since 1958 15 Phosphor thermometry edit Main article Phosphor thermometry Phosphor thermometry is a temperature measurement approach that uses the temperature dependence of certain phosphors For this a phosphor coating is applied to a surface of interest and usually the decay time is the emission parameter that indicates temperature Because the illumination and detection optics can be situated remotely the method may be used for moving surfaces such as high speed motor surfaces Also phosphor may be applied to the end of an optical fiber as an optical analog of a thermocouple citation needed Glow in the dark toys edit Main article Phosphorescence In these applications the phosphor is directly added to the plastic used to mold the toys or mixed with a binder for use as paints ZnS Cu phosphor is used in glow in the dark cosmetic creams frequently used for Halloween make ups Generally the persistence of the phosphor increases as the wavelength increases See also lightstick for chemiluminescence based glowing items Oxygen sensing edit Quenching of the triplet state by O2 which has a triplet ground state as a result of Dexter energy transfer is well known in solutions of phosphorescent heavy metal complexes and doped polymers 16 In recent years phosphorescence porous materials such as Metal organic frameworks and Covalent organic frameworks have shown promising oxygen sensing capabilities for their non linear gas adsorption in ultra low partial pressures of oxygen 17 18 Postage stamps edit Phosphor banded stamps first appeared in 1959 as guides for machines to sort mail 19 Around the world many varieties exist with different amounts of banding 20 Postage stamps are sometimes collected by whether or not they are tagged with phosphor or printed on luminescent paper Radioluminescence edit Main article Radioluminescence Zinc sulfide phosphors are used with radioactive materials where the phosphor was excited by the alpha and beta decaying isotopes to create luminescent paint for dials of watches and instruments radium dials Between 1913 and 1950 radium 228 and radium 226 were used to activate a phosphor made of silver doped zinc sulfide ZnS Ag which gave a greenish glow The phosphor is not suitable to be used in layers thicker than 25 mg cm2 as the self absorption of the light then becomes a problem Furthermore zinc sulfide undergoes degradation of its crystal lattice structure leading to gradual loss of brightness significantly faster than the depletion of radium ZnS Ag coated spinthariscope screens were used by Ernest Rutherford in his experiments discovering atomic nucleus Copper doped zinc sulfide ZnS Cu is the most common phosphor used and yields blue green light Copper and magnesium doped zinc sulfide ZnS Cu Mg yields yellow orange light Tritium is also used as a source of radiation in various products utilizing tritium illumination Electroluminescence edit Main article Electroluminescence Electroluminescence can be exploited in light sources Such sources typically emit from a large area which makes them suitable for backlights of LCD displays The excitation of the phosphor is usually achieved by application of high intensity electric field usually with suitable frequency Current electroluminescent light sources tend to degrade with use resulting in their relatively short operation lifetimes ZnS Cu was the first formulation successfully displaying electroluminescence tested at 1936 by Georges Destriau in Madame Marie Curie laboratories in Paris Powder or AC electroluminescence is found in a variety of backlight and night light applications Several groups offer branded EL offerings e g IndiGlo used in some Timex watches or Lighttape another trade name of an electroluminescent material used in electroluminescent light strips The Apollo space program is often credited with being the first significant use of EL for backlights and lighting 21 White LEDs edit White light emitting diodes are usually blue InGaN LEDs with a coating of a suitable material Cerium III doped YAG YAG Ce3 or Y3Al5O12 Ce3 is often used it absorbs the light from the blue LED and emits in a broad range from greenish to reddish with most of its output in yellow This yellow emission combined with the remaining blue emission gives the white light which can be adjusted to color temperature as warm yellowish or cold bluish white The pale yellow emission of the Ce3 YAG can be tuned by substituting the cerium with other rare earth elements such as terbium and gadolinium and can even be further adjusted by substituting some or all of the aluminium in the YAG with gallium However this process is not one of phosphorescence The yellow light is produced by a process known as scintillation the complete absence of an afterglow being one of the characteristics of the process Some rare earth doped Sialons are photoluminescent and can serve as phosphors Europium II doped b SiAlON absorbs in ultraviolet and visible light spectrum and emits intense broadband visible emission Its luminance and color does not change significantly with temperature due to the temperature stable crystal structure It has a great potential as a green down conversion phosphor for white LEDs a yellow variant also exists a SiAlON 22 For white LEDs a blue LED is used with a yellow phosphor or with a green and yellow SiAlON phosphor and a red CaAlSiN3 based CASN phosphor 23 24 25 White LEDs can also be made by coating near ultraviolet emitting LEDs with a mixture of high efficiency europium based red and blue emitting phosphors plus green emitting copper and aluminium doped zinc sulfide ZnS Cu Al This is a method analogous to the way fluorescent lamps work Some newer white LEDs use a yellow and blue emitter in series to approximate white this technology is used in some Motorola phones such as the Blackberry as well as LED lighting and the original version stacked emitters by using GaN on SiC on InGaP but was later found to fracture at higher drive currents Many white LEDs used in general lighting systems can be used for data transfer as for example in systems that modulate the LED to act as a beacon 26 It is also common for white LEDs to use phosphors other than Ce YAG or to use two or three phosphors to achieve a higher CRI often at the cost of efficiency Examples of additional phosphors are R9 which produces a saturated red nitrides which produce red and aluminates such as lutetium aluminum garnet that produce green Silicate phosphors are brighter but fade more quickly and are used in LCD LED backlights in mobile devices LED phosphors can be placed directly over the die or made into a dome and placed above the LED this approach is known as a remote phosphor 27 Some colored LEDs instead of using a colored LED use a blue LED with a colored phosphor because such an arrangement is more efficient than a colored LED Oxynitride phosphors can also be used in LEDs The precursors used to make the phosphors may degrade when exposed to air 28 Cathode ray tubes edit nbsp Spectra of constituent blue green and red phosphors in a common cathode ray tubeCathode ray tubes produce signal generated light patterns in a typically round or rectangular format Bulky CRTs were used in the black and white household television TV sets that became popular in the 1950s as well as first generation tube based color TVs and most earlier computer monitors CRTs have also been widely used in scientific and engineering instrumentation such as oscilloscopes usually with a single phosphor color typically green Phosphors for such applications may have long afterglow for increased image persistence The phosphors can be deposited as either thin film or as discrete particles a powder bound to the surface Thin films have better lifetime and better resolution but provide less bright and less efficient image than powder ones This is caused by multiple internal reflections in the thin film scattering the emitted light White in black and white The mix of zinc cadmium sulfide and zinc sulfide silver the ZnS Ag Zn Cd S Ag is the white P4 phosphor used in black and white television CRTs Mixes of yellow and blue phosphors are usual Mixes of red green and blue or a single white phosphor can also be encountered Red Yttrium oxide sulfide activated with europium is used as the red phosphor in color CRTs The development of color TV took a long time due to the search for a red phosphor The first red emitting rare earth phosphor YVO4 Eu3 was introduced by Levine and Palilla as a primary color in television in 1964 29 In single crystal form it was used as an excellent polarizer and laser material 30 Yellow When mixed with cadmium sulfide the resulting zinc cadmium sulfide Zn Cd S Ag provides strong yellow light Green Combination of zinc sulfide with copper the P31 phosphor or ZnS Cu provides green light peaking at 531 nm with long glow Blue Combination of zinc sulfide with few ppm of silver the ZnS Ag when excited by electrons provides strong blue glow with maximum at 450 nm with short afterglow with 200 nanosecond duration It is known as the P22B phosphor This material zinc sulfide silver is still one of the most efficient phosphors in cathode ray tubes It is used as a blue phosphor in color CRTs The phosphors are usually poor electrical conductors This may lead to deposition of residual charge on the screen effectively decreasing the energy of the impacting electrons due to electrostatic repulsion an effect known as sticking To eliminate this a thin layer of aluminium about 100 nm is deposited over the phosphors usually by vacuum evaporation and connected to the conductive layer inside the tube This layer also reflects the phosphor light to the desired direction and protects the phosphor from ion bombardment resulting from an imperfect vacuum To reduce the image degradation by reflection of ambient light contrast can be increased by several methods In addition to black masking of unused areas of screen the phosphor particles in color screens are coated with pigments of matching color For example the red phosphors are coated with ferric oxide replacing earlier Cd S Se due to cadmium toxicity blue phosphors can be coated with marine blue CoO nAl2 O3 or ultramarine Na8 Al6 Si6 O24 S2 Green phosphors based on ZnS Cu do not have to be coated due to their own yellowish color 7 Black and white television CRTs edit The black and white television screens require an emission color close to white Usually a combination of phosphors is employed The most common combination is ZnS Ag Zn Cd S Cu Al blue yellow Other ones are ZnS Ag Zn Cd S Ag blue yellow and ZnS Ag ZnS Cu Al Y2O2S Eu3 blue green red does not contain cadmium and has poor efficiency The color tone can be adjusted by the ratios of the components As the compositions contain discrete grains of different phosphors they produce image that may not be entirely smooth A single white emitting phosphor Zn Cd S Ag Au Al overcomes this obstacle Due to its low efficiency it is used only on very small screens The screens are typically covered with phosphor using sedimentation coating where particles suspended in a solution are let to settle on the surface 31 Reduced palette color CRTs edit For displaying of a limited palette of colors there are a few options In beam penetration tubes different color phosphors are layered and separated with dielectric material The acceleration voltage is used to determine the energy of the electrons lower energy ones are absorbed in the top layer of the phosphor while some of the higher energy ones shoot through and are absorbed in the lower layer So either the first color or a mixture of the first and second color is shown With a display with red outer layer and green inner layer the manipulation of accelerating voltage can produce a continuum of colors from red through orange and yellow to green Another method is using a mixture of two phosphors with different characteristics The brightness of one is linearly dependent on electron flux while the other one s brightness saturates at higher fluxes the phosphor does not emit any more light regardless of how many more electrons impact it At low electron flux both phosphors emit together at higher fluxes the luminous contribution of the nonsaturating phosphor prevails changing the combined color 31 Such displays can have high resolution due to absence of two dimensional structuring of RGB CRT phosphors Their color palette is however very limited They were used e g in some older military radar displays Color television CRTs edit This section is missing information about time period of each phosphor composition Please expand the section to include this information Further details may exist on the talk page October 2020 The phosphors in color CRTs need higher contrast and resolution than the black and white ones The energy density of the electron beam is about 100 times greater than in black and white CRTs the electron spot is focused to about 0 2 mm diameter instead of about 0 6 mm diameter of the black and white CRTs Effects related to electron irradiation degradation are therefore more pronounced Color CRTs require three different phosphors emitting in red green and blue patterned on the screen Three separate electron guns are used for color production except for displays that use beam index tube technology which is rare The red phosphor has always been a problem being the dimmest of the three necessitating the brighter green and blue electron beam currents be adjusted down to make them equal the red phosphor s lower brightness This made early color TVs only usable indoors as bright light made it impossible to see the dim picture while portable black and white TVs viewable in outdoor sunlight were already common The composition of the phosphors changed over time as better phosphors were developed and as environmental concerns led to lowering the content of cadmium and later abandoning it entirely The Zn Cd S Ag Cl was replaced with Zn Cd S Cu Al with lower cadmium zinc ratio and then with cadmium free ZnS Cu Al The blue phosphor stayed generally unchanged a silver doped zinc sulfide The green phosphor initially used manganese doped zinc silicate then evolved through silver activated cadmium zinc sulfide to lower cadmium copper aluminium activated formula and then to cadmium free version of the same The red phosphor saw the most changes it was originally manganese activated zinc phosphate then a silver activated cadmium zinc sulfide then the europium III activated phosphors appeared first in an yttrium vanadate matrix then in yttrium oxide and currently in yttrium oxysulfide The evolution of the phosphors was therefore ordered by B G R ZnS Ag Zn2SiO4 Mn Zn3 PO4 2 Mn ZnS Ag Zn Cd S Ag Zn Cd S Ag ZnS Ag Zn Cd S Ag YVO4 Eu3 1964 ZnS Ag Zn Cd S Cu Al Y2O2S Eu3 or Y2O3 Eu3 ZnS Ag ZnS Cu Al or ZnS Au Cu Al Y2O2S Eu3 31 Projection televisions edit For projection televisions where the beam power density can be two orders of magnitude higher than in conventional CRTs some different phosphors have to be used For blue color ZnS Ag Cl is employed However it saturates La Gd OBr Ce Tb3 can be used as an alternative that is more linear at high energy densities For green a terbium activated Gd2O2Tb3 its color purity and brightness at low excitation densities is worse than the zinc sulfide alternative but it behaves linear at high excitation energy densities while zinc sulfide saturates However it also saturates so Y3Al5O12 Tb3 or Y2SiO5 Tb3 can be substituted LaOBr Tb3 is bright but water sensitive degradation prone and the plate like morphology of its crystals hampers its use these problems are solved now so it is gaining use due to its higher linearity Y2O2S Eu3 is used for red emission 31 Standard phosphor types editStandard phosphor types 32 33 Phosphor Composition Color Wavelength Peak width Persistence Usage NotesP1 GJ Zn2SiO4 Mn Willemite Green 525 nm 40 nm 34 1 100ms CRT Lamp Oscilloscopes and monochrome monitorsP2 ZnS Cu Ag B Blue Green 543 nm Long CRT OscilloscopesP3 Zn8 BeSi5O19 Mn Yellow 602 nm Medium 13 ms CRT Amber monochrome monitorsP4 ZnS Ag Zn Cd S Ag White 565 540 nm Short CRT Black and white TV CRTs and display tubes P4 Cd free ZnS Ag ZnS Cu Y2O2S Eu White Short CRT Black and white TV CRTs and display tubes Cd free P5 CaWO4 W Blue 430 nm Very Short CRT FilmP6 ZnS Ag ZnS CdS Ag White 565 460 nm Short CRTP7 Zn Cd S Cu Blue with Yellow persistence 558 440 nm Long CRT Radar PPI old EKG monitors early oscilloscopesP10 KCl green absorbing scotophor Long Dark trace CRTs Radar screens turns from translucent white to dark magenta stays changed until erased by heating or infrared lightP11 BE ZnS Ag Cl or ZnS Zn Blue 460 nm 0 01 1 ms CRT VFD Display tubes and VFDs Oscilloscopes for fast photographic recording 35 P12 Zn Mg F2 Mn Orange 590 nm Medium long CRT RadarP13 MgSi2O6 Mn Reddish Orange Reddish Orange 640 nm Medium CRT Flying spot scanning systems and photographic applicationsP14 ZnS Ag on ZnS CdS Cu Blue with Orange persistence Medium long CRT Radar PPI old EKG monitorsP15 ZnO Zn Blue Green 504 391 nm Extremely Short CRT Television pickup by flying spot scanningP16 CaMgSi2O6 Ce Bluish Purple Bluish Purple 380 nm Very Short CRT Flying spot scanning systems and photographic applicationsP17 ZnO ZnCdS Cu Blue Yellow 504 391 nm Blue Short Yellow Long CRTP18 CaMgSi2O6 Ti BeSi2O6 Mn white white 545 405 nm Medium to Short CRTP19 LF KF MgF2 Mn Orange Yellow 590 nm Long CRT Radar screensP20 KA Zn Cd S Ag or Zn Cd S Cu Yellow green 555 nm 1 100 ms CRT Display tubesP21 MgF2 Mn2 Reddish 605 nm CRT Radar Registered by Allen B DuMont LaboratoriesP22R Y2O2S Eu Fe2O3 Red 611 nm Short CRT Red phosphor for TV screensP22G ZnS Cu Al Green 530 nm Short CRT Green phosphor for TV screensP22B ZnS Ag Co on Al2O3 Blue Short CRT Blue phosphor for TV screensP23 ZnS Ag Zn Cd S Ag White 575 460 nm Short CRT Direct viewing television Registered by United States Radium Corporation P24 GE ZnO Zn Green 505 nm 1 10 ms VFD most common phosphor in vacuum fluorescent displays 36 P25 CaSi2O6 Pb Mn Orange Orange 610 nm Medium CRT Military Displays 7UP25 CRTP26 LC KF MgF2 Mn Orange 595 nm Long CRT Radar screensP27 ZnPO4 Mn Reddish Orange Reddish Orange 635 nm Medium CRT Color TV monitor serviceP28 KE Zn Cd S Cu Cl Yellow Medium CRT Display tubesP29 Alternating P2 and P25 stripes Blue Green Orange stripes Medium CRT Radar screensP31 GH ZnS Cu or ZnS Cu Ag Yellowish green 0 01 1 ms CRT Oscilloscopes and monochrome monitorsP33 LD MgF2 Mn Orange 590 nm gt 1sec CRT Radar screensP34 Bluish Green Yellow Green Very Long CRT P35 ZnS ZnSe Ag Blue White Blue White 455 nm Medium Short CRT Photographic registration on orthochromatic film materialsP38 LK Zn Mg F2 Mn Orange Yellow 590 nm Long CRT Radar screensP39 GR Zn2SiO4 Mn As Green 525 nm Long CRT Display tubesP40 GA ZnS Ag Zn Cd S Cu White Long CRT Display tubesP43 GY Gd2O2S Tb Yellow green 545 nm Medium CRT Display tubes Electronic Portal Imaging Devices EPIDs used in radiation therapy linear accelerators for cancer treatmentP45 WB Y2O2S Tb White 545 nm Short CRT ViewfindersP46 KG Y3Al5O12 Ce Green 530 nm Very short 70ns CRT Beam index tubeP47 BH Y2SiO5 Ce Blue 400 nm Very short CRT Beam index tubeP53 KJ Y3Al5O12 Tb Yellow green 544 nm Short CRT Projection tubesP55 BM ZnS Ag Al Blue 450 nm Short CRT Projection tubesZnS Ag Blue 450 nm CRT ZnS Cu Al or ZnS Cu Au Al Green 530 nm CRT Zn Cd S Cu Cl Zn Cd S Ag Cl White CRT Y2SiO5 Tb Green 545 nm CRT Projection tubesY2OS Tb Green 545 nm CRT Display tubesY3 Al Ga 5O12 Ce Green 520 nm Short CRT Beam index tubeY3 Al Ga 5O12 Tb Yellow green 544 nm Short CRT Projection tubesInBO3 Tb Yellow green 550 nm CRT InBO3 Eu Yellow 588 nm CRT InBO3 Tb InBO3 Eu amber CRT Computer displaysInBO3 Tb InBO3 Eu ZnS Ag White CRT Ba Eu Mg2Al16O27 Blue Lamp Trichromatic fluorescent lamps Ce Tb MgAl11O19 Green 546 nm 9 nm Lamp Trichromatic fluorescent lamps 34 BAM BaMgAl10O17 Eu Mn Blue 450 nm Lamp displays Trichromatic fluorescent lampsBaMg2Al16O27 Eu II Blue 450 nm 52 nm Lamp Trichromatic fluorescent lamps 34 BAM BaMgAl10O17 Eu Mn Blue Green 456 nm 514 nm Lamp BaMg2Al16O27 Eu II Mn II Blue Green 456 nm 514 nm 50 nm 50 34 LampCe0 67Tb0 33MgAl11O19 Ce Tb Green 543 nm Lamp Trichromatic fluorescent lampsZn2SiO4 Mn Sb2O3 Green 528 nm Lamp CaSiO3 Pb Mn Orange Pink 615 nm 83 nm 34 LampCaWO4 Scheelite Blue 417 nm Lamp CaWO4 Pb Blue 433 nm 466 nm 111 nm Lamp Wide bandwidth 34 MgWO4 Blue pale 473 nm 118 nm Lamp Wide bandwidth deluxe blend component 34 Sr Eu Ba Ca 5 PO4 3Cl Blue Lamp Trichromatic fluorescent lampsSr5Cl PO4 3 Eu II Blue 447 nm 32 nm 34 Lamp Ca Sr Ba 3 PO4 2Cl2 Eu Blue 452 nm Lamp Sr Ca Ba 10 PO4 6Cl2 Eu Blue 453 nm Lamp Trichromatic fluorescent lampsSr2P2O7 Sn II Blue 460 nm 98 nm Lamp Wide bandwidth deluxe blend component 34 Sr6P5BO20 Eu Blue Green 480 nm 82 nm 34 Lamp Ca5F PO4 3 Sb Blue 482 nm 117 nm Lamp Wide bandwidth 34 Ba Ti 2P2O7 Ti Blue Green 494 nm 143 nm Lamp Wide bandwidth deluxe blend component 34 3Sr3 PO4 2 SrF2 Sb Mn Blue 502 nm Lamp Sr5F PO4 3 Sb Mn Blue Green 509 nm 127 nm Lamp Wide bandwidth 34 Sr5F PO4 3 Sb Mn Blue Green 509 nm 127 nm Lamp Wide bandwidth 34 LaPO4 Ce Tb Green 544 nm Lamp Trichromatic fluorescent lamps La Ce Tb PO4 Green Lamp Trichromatic fluorescent lamps La Ce Tb PO4 Ce Tb Green 546 nm 6 nm Lamp Trichromatic fluorescent lamps 34 Ca3 PO4 2 CaF2 Ce Mn Yellow 568 nm Lamp Ca Zn Mg 3 PO4 2 Sn Orange pink 610 nm 146 nm Lamp Wide bandwidth blend component 34 Zn Sr 3 PO4 2 Mn Orange Red 625 nm Lamp Sr Mg 3 PO4 2 Sn Orange pinkish white 626 nm 120 nm Fluorescent lamps Wide bandwidth deluxe blend component 34 Sr Mg 3 PO4 2 Sn II Orange red 630 nm Fluorescent lamps Ca5F PO4 3 Sb Mn 3800K Fluorescent lamps Lite white blend 34 Ca5 F Cl PO4 3 Sb Mn White Cold Warm Fluorescent lamps 2600 to 9900 K for very high output lamps 34 Y Eu 2O3 Red Lamp Trichromatic fluorescent lampsY2O3 Eu III Red 611 nm 4 nm Lamp Trichromatic fluorescent lamps 34 Mg4 F GeO6 Mn Red 658 nm 17 nm High pressure mercury lamps 34 Mg4 F Ge Sn O6 Mn Red 658 nm Lamp Y P V O4 Eu Orange Red 619 nm Lamp YVO4 Eu Orange Red 619 nm High Pressure Mercury and Metal Halide Lamps Y2O2S Eu Red 626 nm Lamp 3 5 MgO 0 5 MgF2 GeO2 Mn Red 655 nm Lamp 3 5 MgO 0 5 MgF2 GeO2 MnMg5As2O11 Mn Red 660 nm High pressure mercury lamps 1960s SrAl2O7 Pb Ultraviolet 313 nm Special fluorescent lamps for medical use UltravioletCAM LaMgAl11O19 Ce Ultraviolet 340 nm 52 nm Black light fluorescent lamps UltravioletLAP LaPO4 Ce Ultraviolet 320 nm 38 nm Medical and scientific UV lamps UltravioletSAC SrAl12O19 Ce Ultraviolet 295 nm 34 nm Lamp UltravioletSrAl11Si0 75O19 Ce0 15Mn0 15 Green 515 nm 22 nm Lamp Monochromatic lamps for copiers 37 BSP BaSi2O5 Pb Ultraviolet 350 nm 40 nm Lamp UltravioletSrFB2O3 Eu II Ultraviolet 366 nm Lamp UltravioletSBE SrB4O7 Eu Ultraviolet 368 nm 15 nm Lamp UltravioletSMS Sr2MgSi2O7 Pb Ultraviolet 365 nm 68 nm Lamp UltravioletMgGa2O4 Mn II Blue Green Lamp Black light displaysVarious edit Some other phosphors commercially available for use as X ray screens neutron detectors alpha particle scintillators etc are Gd2O2S Tb P43 green peak at 545 nm 1 5 ms decay to 10 low afterglow high X ray absorption for X ray neutrons and gamma Gd2O2S Eu red 627 nm 850 ms decay afterglow high X ray absorption for X ray neutrons and gamma Gd2O2S Pr green 513 nm 7 ms decay no afterglow high X ray absorption for X ray neutrons and gamma Gd2O2S Pr Ce F green 513 nm 4 ms decay no afterglow high X ray absorption for X ray neutrons and gamma Y2O2S Tb P45 white 545 nm 1 5 ms decay low afterglow for low energy X ray Y2O2S Eu P22R red 627 nm 850 ms decay afterglow for low energy X ray Y2O2S Pr white 513 nm 7 ms decay no afterglow for low energy X ray Zn0 5 Cd0 4 S Ag HS green 560 nm 80 ms decay afterglow efficient but low res X ray Zn0 4 Cd0 6 S Ag HSr red 630 nm 80 ms decay afterglow efficient but low res X ray CdWO4 blue 475 nm 28 ms decay no afterglow intensifying phosphor for X ray and gamma CaWO4 blue 410 nm 20 ms decay no afterglow intensifying phosphor for X ray MgWO4 white 500 nm 80 ms decay no afterglow intensifying phosphor Y2SiO5 Ce P47 blue 400 nm 120 ns decay no afterglow for electrons suitable for photomultipliers YAlO3 Ce YAP blue 370 nm 25 ns decay no afterglow for electrons suitable for photomultipliers Y3Al5O12 Ce YAG green 550 nm 70 ns decay no afterglow for electrons suitable for photomultipliers Y3 Al Ga 5O12 Ce YGG green 530 nm 250 ns decay low afterglow for electrons suitable for photomultipliers CdS In green 525 nm lt 1 ns decay no afterglow ultrafast for electrons ZnO Ga blue 390 nm lt 5 ns decay no afterglow ultrafast for electrons ZnO Zn P15 blue 495 nm 8 ms decay no afterglow for low energy electrons Zn Cd S Cu Al P22G green 565 nm 35 ms decay low afterglow for electrons ZnS Cu Al Au P22G green 540 nm 35 ms decay low afterglow for electrons ZnCdS Ag Cu P20 green 530 nm 80 ms decay low afterglow for electrons ZnS Ag P11 blue 455 nm 80 ms decay low afterglow for alpha particles and electrons anthracene blue 447 nm 32 ns decay no afterglow for alpha particles and electrons plastic EJ 212 blue 400 nm 2 4 ns decay no afterglow for alpha particles and electrons Zn2SiO4 Mn P1 green 530 nm 11 ms decay low afterglow for electrons ZnS Cu GS green 520 nm decay in minutes long afterglow for X rays NaI Tl for X ray alpha and electrons CsI Tl green 545 nm 5 ms decay afterglow for X ray alpha and electrons 6LiF ZnS Ag ND blue 455 nm 80 ms decay for thermal neutrons 6LiF ZnS Cu Al Au NDg green 565 nm 35 ms decay for neutrons Cerium doped YAG phosphor yellow used in white LEDs for turning blue to white light with a broad spectrum of lightSee also editCathodoluminescence Laser Luminophore PhotoluminescenceReferences edit Emsley John 2000 The Shocking History of Phosphorus London Macmillan ISBN 978 0 330 39005 7 Xie Rong Jun Hirosaki Naoto 2007 Silicon based oxynitride and nitride phosphors for white LEDs A review Sci Technol Adv Mater 8 7 8 588 Bibcode 2007STAdM 8 588X doi 10 1016 j stam 2007 08 005 nbsp Li Hui Li Hirosaki Naoto Xie Rong Jun Suehiro Takayuki Mitomo Mamoru 2007 Fine yellow a SiAlON Eu phosphors for white LEDs prepared by the gas reduction nitridation method Sci Technol Adv Mater 8 7 8 601 Bibcode 2007STAdM 8 601L doi 10 1016 j stam 2007 09 003 nbsp Kane Raymond and Sell Heinz 2001 Revolution in lamps a chronicle of 50 years of progress 2nd ed The Fairmont Press ISBN 0 88173 378 4 Chapter 5 extensively discusses history application and manufacturing of phosphors for lamps a b Matsuzawa T Aoki Y Takeuchi N Murayama Y 1996 08 01 A New Long Phosphorescent Phosphor with High Brightness SrAl2O4 Eu2 Dy3 Journal of the Electrochemical Society 143 8 2670 2673 Bibcode 1996JElS 143 2670M doi 10 1149 1 1837067 ISSN 0013 4651 US5424006A Phosphorescent phosphor issued 1994 02 25 a b c d e f g Peter W Hawkes 1 October 1990 Advances in electronics and electron physics Academic Press pp 350 ISBN 978 0 12 014679 6 Retrieved 9 January 2012 Bizarri G Moine B 2005 On phosphor degradation mechanism thermal treatment effects Journal of Luminescence 113 3 4 199 Bibcode 2005JLum 113 199B doi 10 1016 j jlumin 2004 09 119 Lakshmanan p 171 Tanno Hiroaki Fukasawa Takayuki Zhang Shuxiu Shinoda Tsutae Kajiyama Hiroshi 2009 Lifetime Improvement of BaMgAl10O17 Eu2 Phosphor by Hydrogen Plasma Treatment Japanese Journal of Applied Physics 48 9 092303 Bibcode 2009JaJAP 48i2303T doi 10 1143 JJAP 48 092303 S2CID 94464554 Ntwaeaborwa O M Hillie K T Swart H C 2004 Degradation of Y2O3 Eu phosphor powders Physica Status Solidi C 1 9 2366 Bibcode 2004PSSCR 1 2366N doi 10 1002 pssc 200404813 Wang Ching Wu Sheu Tong Ji Su Yan Kuin Yokoyama Meiso 1997 Deep Traps and Mechanism of Brightness Degradation in Mn doped ZnS Thin Film Electroluminescent Devices Grown by Metal Organic Chemical Vapor Deposition Japanese Journal of Applied Physics 36 5A 2728 Bibcode 1997JaJAP 36 2728W doi 10 1143 JJAP 36 2728 S2CID 98131548 Lakshmanan pp 51 76 PPT presentation in Polish Link to achieved version Original site isn t available Tubedevices com Archived from the original on 2013 12 28 Retrieved 2016 12 15 a href Template Cite web html title Template Cite web cite web a CS1 maint bot original URL status unknown link Vacuum light sources High speed stroboscopic light sources data sheet PDF Ferranti Ltd August 1958 Archived PDF from the original on 20 September 2016 Retrieved 7 May 2017 Lehner P Staudinger C Borisov S M Klimant l 2014 Ultra sensitive optical oxygen sensors for characterization of nearly anoxic systems Nature Communications 5 4460 Bibcode 2014NatCo 5 4460L doi 10 1038 ncomms5460 PMC 4109599 PMID 25042041 Hamzehpoor E Ruchlin C Tao Y Liu C H Titi H M Perepichka D F 2022 Efficient room temperature phosphorescence of covalent organic frameworks through covalent halogen doping Nature Chemistry 15 1 83 90 doi 10 1038 s41557 022 01070 4 PMID 36302870 S2CID 253183290 Xie Z Ma L deKrafft K E Jin A Lin W 2010 Porous phosphorescent coordination polymers for oxygen sensing J Am Chem Soc 132 3 922 923 doi 10 1021 ja909629f PMID 20041656 SEEING PHOSPHOR BANDS on U K STAMPS Archived 2015 10 19 at the Wayback Machine Phosphor Bands Archived 2017 03 17 at the Wayback Machine Archived copy PDF Archived PDF from the original on 2016 12 21 Retrieved 2017 02 12 a href Template Cite web html title Template Cite web cite web a CS1 maint archived copy as title link XTECH NIKKEI Sharp to Employ White LED Using Sialon NIKKEI XTECH Retrieved 2019 01 10 Youn Gon Park et al Luminescence and temperature dependency of b SiAlON phosphor Samsung Electro Mechanics Co Archived from the original on 2010 04 12 Retrieved 2009 09 24 Hideyoshi Kume Nikkei Electronics Sep 15 2009 Sharp to Employ White LED Using Sialon Archived from the original on 2012 02 23 Naoto Hirosaki et al 2005 New sialon phosphors and white LEDs Oyo Butsuri 74 11 1449 Archived from the original on 2010 04 04 Fudin M S et al 2014 Frequency characteristics of modern LED phosphor materials Scientific and Technical Journal of Information Technologies Mechanics and Optics 14 6 71 Archived from the original on 2015 06 26 Bush Steve March 14 2014 Discussing LED lighting phosphors Setlur Anant A 1 December 2009 Phosphors for LED based Solid State Lighting PDF The Electrochemical Society Interface 18 4 32 36 doi 10 1149 2 F04094IF Retrieved 5 December 2022 Levine Albert K Palilla Frank C 1964 A new highly efficient red emitting cathodoluminescent phosphor YVO4 Eu for color television Applied Physics Letters 5 6 118 Bibcode 1964ApPhL 5 118L doi 10 1063 1 1723611 Fields R A Birnbaum M Fincher C L 1987 Highly efficient Nd YVO4 diode laser end pumped laser Applied Physics Letters 51 23 1885 Bibcode 1987ApPhL 51 1885F doi 10 1063 1 98500 a b c d Lakshmanan p 54 Shionoya Shigeo 1999 VI Phosphors for cathode ray tubes Phosphor handbook Boca Raton Fla CRC Press ISBN 978 0 8493 7560 6 Jankowiak Patrick Cathode Ray Tube Phosphors PDF bunkerofdoom com Archived PDF from the original on 19 January 2013 Retrieved 1 May 2012 unreliable source a b c d e f g h i j k l m n o p q r s t u Osram Sylvania fluorescent lamps Archived from the original on July 24 2011 Retrieved 2009 06 06 Keller Peter 1991 The Cathode Ray Tube Technology History and Applications Palisades Press p 17 ISBN 0963155903 VFD Futaba Corporation 27 February 2021 Lagos C 1974 Strontium aluminate phosphor activated by cerium and manganese U S patent 3 836 477Bibliography editArunachalam Lakshmanan 2008 Luminescence and Display Phosphors Phenomena and Applications Nova Publishers ISBN 978 1 60456 018 3 External links edit nbsp Look up phosphor in Wiktionary the free dictionary a history of electroluminescent displays Archived 2012 04 30 at the Wayback Machine Fluorescence Phosphorescence CRT Phosphor Characteristics P numbers Composition of CRT phosphors Silicon based oxynitride and nitride phosphors for white LEDs A review 1 Archived 2023 04 10 at the Wayback Machine amp 2 Archived 2023 04 10 at the Wayback Machine RCA Manual Fluorescent screens P1 to P24 Inorganic Phosphors Compositions Preparation and Optical Properties William M Yen and Marvin J Weber Archived 2016 03 06 at the Wayback Machine Retrieved from https en wikipedia org w index php title Phosphor amp oldid 1195332999, wikipedia, wiki, book, books, library,

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