A flexible organic light-emitting diode (FOLED) is a type of organic light-emitting diode (OLED) incorporating a flexible plastic substrate on which the electroluminescentorganic semiconductor is deposited. This enables the device to be bent or rolled while still operating. Currently the focus of research in industrial and academic groups, flexible OLEDs form one method of fabricating a rollable display.
Demonstration of a battery-driven flexible OLED lamp from Merck KGaA
An OLED emits light due to the electroluminescence of thin films of organic semiconductors approximately 100 nm thick. Regular OLEDs are usually fabricated on a glass substrate, but by replacing glass with a flexible plastic such as polyethylene terephthalate (PET)[1] among others,[2] OLEDs can be made both bendable and lightweight.
Such materials may not be suitable for comparable devices based on inorganicsemiconductors due to the need for lattice matching and the high temperature fabrication procedure involved.[3]
In contrast, flexible OLED devices can be fabricated by deposition of the organic layer onto the substrate using a method derived from inkjet printing,[4][5] allowing the inexpensive and roll-to-roll fabrication of printed electronics.
Flexible OLEDs may be used in the production of rollable displays, electronic paper, or bendable displays which can be integrated into clothing, wallpaper or other curved surfaces.[6][7][8] Prototype displays have been exhibited by companies such as Sony, which are capable of being rolled around the width of a pencil.[9]
Both flexible substrate itself as well as the process of bending the device introduce stress into the materials. There may be residual stress from the deposition of layers onto a flexible substrate,[10] thermal stresses due to the different coefficient of thermal expansion of materials in the device,[11] in addition to the external stress from the bending of the device.[12]
Stress introduced into the organic layers may lower the efficiency or brightness of the device as it is deformed, or cause complete breakdown of the device altogether. Indium tin oxide (ITO), the material most commonly used as the transparent anode, is brittle. Fracture of the anode can occur which can increase the sheet resistance of the ITO or disrupt the layered structure of the OLED.[13] Although ITO is the most common and best understood anode material used in OLEDs, research has been undertaken into alternative materials that are better suited for flexible applications including carbon nanotubes.[14][15]
Encapsulation is another challenge for flexible OLED devices. The materials in an OLED are sensitive to air and moisture which lead to degradation of the materials themselves as well as quenching of excited states within the molecule. The common method of encapsulation for regular OLEDs is to seal the organic layer between glass. Flexible encapsulation methods are generally not as effective a barrier to air and moisture as glass, and current research aims to improve the encapsulation of flexible organic light emitting diodes.[16][17]
^Gustafsson, G.; Cao, Y.; Treacy, G. M.; Klavetter, F.; Colaneri, N.; Heeger, A. J. (1992). "Flexible light-emitting diodes made from soluble conducting polymers". Nature. 357 (6378): 477. Bibcode:1992Natur.357..477G. doi:10.1038/357477a0. S2CID 4366944.
^MacDonald, W. A. (2004). "Engineered films for display technologies". Journal of Materials Chemistry. 14: 4–10. doi:10.1039/B310846P.
^Burrows, P. E.; Gu, G.; Bulovic, V.; Shen, Z.; Forrest, S. R.; Thompson, M. E. (1997). "Achieving full-color organic light-emitting devices for lightweight, flat-panel displays". IEEE Transactions on Electron Devices. 44 (8): 1188–1203. Bibcode:1997ITED...44.1188B. doi:10.1109/16.605453.
^Hebner, T. R.; Wu, C. C.; Marcy, D.; Lu, M. H.; Sturm, J. C. (1998). "Ink-jet printing of doped polymers for organic light emitting devices". Applied Physics Letters. 72 (5): 519–521. Bibcode:1998ApPhL..72..519H. doi:10.1063/1.120807. S2CID 119648364.
^Bharathan, Jayesh; Yang, Yang (1998). "Polymer electroluminescent devices processed by inkjet printing: I. Polymer light-emitting logo". Applied Physics Letters. 72 (21): 2660–2662. Bibcode:1998ApPhL..72.2660B. doi:10.1063/1.121090.
^Brandon Bailey (31 January 2011). "Flexible electronic display will get Army field test". Los Angeles Times. Retrieved 3 February 2011.
^"'Light emitting wallpaper' could replace bulbs". BBC News. 30 December 2009. Retrieved 3 February 2011.
^Michael Fitzpatrick (5 July 2010). "Haptics brings a personal touch to technology". BBC News. Retrieved 3 February 2011.
^Candace Lombardi (26 May 2010). "Sony unveils ultrathin rollable OLED". CNET News. Retrieved 3 February 2011.
^Chiang, C.-J.; Winscom, C.; Monkman, A. (2010). "Electroluminescence characterization of FOLED devices under two type of external stresses caused by bending". Organic Electronics. 11 (11): 1870–1875. doi:10.1016/j.orgel.2010.08.021.
^Hsueh, C. H. (2002). "Thermal stresses in elastic multilayer systems". Thin Solid Films. 418 (2): 182–188. Bibcode:2002TSF...418..182H. doi:10.1016/S0040-6090(02)00699-5.
^Leterrier, Y.; Médico, L.; Månson, J.-A. E.; Betz, U.; Escolà, M. F.; Kharrazi Olsson, M.; Atamny, F. (2004). "Mechanical integrity of transparent conductive oxide films for flexible polymer-based displays". Thin Solid Films. 460 (1–2): 156–166. Bibcode:2004TSF...460..156L. doi:10.1016/j.tsf.2004.01.052.
^Choi, K.-H.; Nam, H.-J.; Jeong, J.-A.; Cho, S.-W.; Kim, H.-K.; Kang, J.-W.; Kim, D.-G.; Cho, W.-J. (2009). "Highly flexible and transparent InZnSnOx/Ag/InZnSnOx multilayer electrode for flexible organic light emitting diodes". Applied Physics Letters. 92 (22): 223302. Bibcode:2008ApPhL..92v3302C. doi:10.1063/1.2937845.
^Aguirre, C. M.; Auvray, S.; Pigeon, S.; Izquierdo, R.; Desjardins, P.; Martel, R. (2006). "Carbon nanotube sheets as electrodes in organic light-emitting diodes" (PDF). Applied Physics Letters. 88 (18): 183104. Bibcode:2006ApPhL..88r3104A. doi:10.1063/1.2199461.
^Han, J.-M.; Han, J.-W.; Chun, J.-Y.; Ok, C.-H.; Seo, D.-S. (2008). "Novel Encapsulation Method for Flexible Organic Light-Emitting Diodes using Poly(dimethylsiloxane)". Japanese Journal of Applied Physics. 47 (12): 8986–8988. Bibcode:2008JaJAP..47.8986H. doi:10.1143/JJAP.47.8986. S2CID 120700195.
^Liu, S.; Zhang, D.; Li, Y.; Duan, L.; Dong, G.; Wang, L.; Qiu, Y. (2008). "New hybrid encapsulation for flexible organic light-emitting devices on plastic substrates". Chinese Science Bulletin. 53 (6): 958–960. Bibcode:2008SciBu..53..958L. doi:10.1007/s11434-008-0088-9.
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Are Foldable Laptops the Future?
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flexible, organic, light, emitting, diode, flexible, organic, light, emitting, diode, foled, type, organic, light, emitting, diode, oled, incorporating, flexible, plastic, substrate, which, electroluminescent, organic, semiconductor, deposited, this, enables, . A flexible organic light emitting diode FOLED is a type of organic light emitting diode OLED incorporating a flexible plastic substrate on which the electroluminescent organic semiconductor is deposited This enables the device to be bent or rolled while still operating Currently the focus of research in industrial and academic groups flexible OLEDs form one method of fabricating a rollable display Flexible OLED displays on foldable smartphones Contents 1 Technical details and applications 2 Disadvantages 3 See also 4 References 5 External linksTechnical details and applications editSee also Organic LED Working principle and List of OLED advantages nbsp Demonstration of a battery driven flexible OLED lamp from Merck KGaA An OLED emits light due to the electroluminescence of thin films of organic semiconductors approximately 100 nm thick Regular OLEDs are usually fabricated on a glass substrate but by replacing glass with a flexible plastic such as polyethylene terephthalate PET 1 among others 2 OLEDs can be made both bendable and lightweight Such materials may not be suitable for comparable devices based on inorganic semiconductors due to the need for lattice matching and the high temperature fabrication procedure involved 3 In contrast flexible OLED devices can be fabricated by deposition of the organic layer onto the substrate using a method derived from inkjet printing 4 5 allowing the inexpensive and roll to roll fabrication of printed electronics Flexible OLEDs may be used in the production of rollable displays electronic paper or bendable displays which can be integrated into clothing wallpaper or other curved surfaces 6 7 8 Prototype displays have been exhibited by companies such as Sony which are capable of being rolled around the width of a pencil 9 Disadvantages editSee also List of OLED disadvantages Both flexible substrate itself as well as the process of bending the device introduce stress into the materials There may be residual stress from the deposition of layers onto a flexible substrate 10 thermal stresses due to the different coefficient of thermal expansion of materials in the device 11 in addition to the external stress from the bending of the device 12 Stress introduced into the organic layers may lower the efficiency or brightness of the device as it is deformed or cause complete breakdown of the device altogether Indium tin oxide ITO the material most commonly used as the transparent anode is brittle Fracture of the anode can occur which can increase the sheet resistance of the ITO or disrupt the layered structure of the OLED 13 Although ITO is the most common and best understood anode material used in OLEDs research has been undertaken into alternative materials that are better suited for flexible applications including carbon nanotubes 14 15 Encapsulation is another challenge for flexible OLED devices The materials in an OLED are sensitive to air and moisture which lead to degradation of the materials themselves as well as quenching of excited states within the molecule The common method of encapsulation for regular OLEDs is to seal the organic layer between glass Flexible encapsulation methods are generally not as effective a barrier to air and moisture as glass and current research aims to improve the encapsulation of flexible organic light emitting diodes 16 17 See also editFlexible electronics Organic light emitting diode Phosphorescent organic light emitting diode Rollable displayReferences edit Gustafsson G Cao Y Treacy G M Klavetter F Colaneri N Heeger A J 1992 Flexible light emitting diodes made from soluble conducting polymers Nature 357 6378 477 Bibcode 1992Natur 357 477G doi 10 1038 357477a0 S2CID 4366944 MacDonald W A 2004 Engineered films for display technologies Journal of Materials Chemistry 14 4 10 doi 10 1039 B310846P Burrows P E Gu G Bulovic V Shen Z Forrest S R Thompson M E 1997 Achieving full color organic light emitting devices for lightweight flat panel displays IEEE Transactions on Electron Devices 44 8 1188 1203 Bibcode 1997ITED 44 1188B doi 10 1109 16 605453 Hebner T R Wu C C Marcy D Lu M H Sturm J C 1998 Ink jet printing of doped polymers for organic light emitting devices Applied Physics Letters 72 5 519 521 Bibcode 1998ApPhL 72 519H doi 10 1063 1 120807 S2CID 119648364 Bharathan Jayesh Yang Yang 1998 Polymer electroluminescent devices processed by inkjet printing I Polymer light emitting logo Applied Physics Letters 72 21 2660 2662 Bibcode 1998ApPhL 72 2660B doi 10 1063 1 121090 Brandon Bailey 31 January 2011 Flexible electronic display will get Army field test Los Angeles Times Retrieved 3 February 2011 Light emitting wallpaper could replace bulbs BBC News 30 December 2009 Retrieved 3 February 2011 Michael Fitzpatrick 5 July 2010 Haptics brings a personal touch to technology BBC News Retrieved 3 February 2011 Candace Lombardi 26 May 2010 Sony unveils ultrathin rollable OLED CNET News Retrieved 3 February 2011 Chiang C J Winscom C Monkman A 2010 Electroluminescence characterization of FOLED devices under two type of external stresses caused by bending Organic Electronics 11 11 1870 1875 doi 10 1016 j orgel 2010 08 021 Hsueh C H 2002 Thermal stresses in elastic multilayer systems Thin Solid Films 418 2 182 188 Bibcode 2002TSF 418 182H doi 10 1016 S0040 6090 02 00699 5 Chiang C J Winscom C Bull S Monkman A 2009 Mechanical modeling of flexible OLED devices Organic Electronics 10 7 1268 1274 doi 10 1016 j orgel 2009 07 003 Leterrier Y Medico L Manson J A E Betz U Escola M F Kharrazi Olsson M Atamny F 2004 Mechanical integrity of transparent conductive oxide films for flexible polymer based displays Thin Solid Films 460 1 2 156 166 Bibcode 2004TSF 460 156L doi 10 1016 j tsf 2004 01 052 Choi K H Nam H J Jeong J A Cho S W Kim H K Kang J W Kim D G Cho W J 2009 Highly flexible and transparent InZnSnOx Ag InZnSnOx multilayer electrode for flexible organic light emitting diodes Applied Physics Letters 92 22 223302 Bibcode 2008ApPhL 92v3302C doi 10 1063 1 2937845 Aguirre C M Auvray S Pigeon S Izquierdo R Desjardins P Martel R 2006 Carbon nanotube sheets as electrodes in organic light emitting diodes PDF Applied Physics Letters 88 18 183104 Bibcode 2006ApPhL 88r3104A doi 10 1063 1 2199461 Han J M Han J W Chun J Y Ok C H Seo D S 2008 Novel Encapsulation Method for Flexible Organic Light Emitting Diodes using Poly dimethylsiloxane Japanese Journal of Applied Physics 47 12 8986 8988 Bibcode 2008JaJAP 47 8986H doi 10 1143 JJAP 47 8986 S2CID 120700195 Liu S Zhang D Li Y Duan L Dong G Wang L Qiu Y 2008 New hybrid encapsulation for flexible organic light emitting devices on plastic substrates Chinese Science Bulletin 53 6 958 960 Bibcode 2008SciBu 53 958L doi 10 1007 s11434 008 0088 9 External links editAre Foldable Laptops the Future Retrieved from https en wikipedia org w index php title Flexible organic light emitting diode amp oldid 1146846421, wikipedia, wiki, book, books, library,
