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Prototype OLED lighting panels
Demonstration of a flexible OLED device

An organic light-emitting diode (OLED) is a digital displays in devices such as television screens, computer monitors, portable systems such as mobile phones, handheld game consoles and PDAs. A major area of research is the development of white OLED devices for use in solid-state lighting applications.[1][2][3]

There are two main families of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell (LEC) which has a slightly different mode of operation. OLED displays can use either passive-matrix (PMOLED) or active-matrix addressing schemes. Active-matrix OLEDs (AMOLED) require a thin-film transistor backplane to switch each individual pixel on or off, but allow for higher resolution and larger display sizes.

An OLED display works without a backlight; thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions (such as a dark room), an OLED screen can achieve a higher contrast ratio than an LCD, regardless of whether the LCD uses cold cathode fluorescent lamps or an LED backlight.


  • History 1
  • Working principle 2
  • Material technologies 3
    • Small molecules 3.1
    • Polymer light-emitting diodes 3.2
    • Phosphorescent materials 3.3
  • Device architectures 4
    • Structure 4.1
    • Patterning technologies 4.2
    • Backplane technologies 4.3
  • Fabrication 5
  • Advantages 6
  • Disadvantages 7
  • Manufacturers and commercial uses 8
    • Fashion 8.1
    • Samsung applications 8.2
    • Sony applications 8.3
    • LG applications 8.4
    • Mitsubishi applications 8.5
    • Recom Group/video name tag applications 8.6
    • BMW 8.7
  • Research 9
  • See also 10
  • References 11
  • Further reading 12
  • External links 13


André Bernanose and co-workers at the acridine orange, either deposited on or dissolved in cellulose or cellophane thin films. The proposed mechanism was either direct excitation of the dye molecules or excitation of electrons.[4][5][6][7]

In 1960

  • Structure and working principle of OLEDs and electroluminescent displays
  • Tutorial on the working principle of OLEDs at Ghent University
  • MIT introduction to OLED technology (video)
  • Historical list of OLED products from 1996 to present

External links

  • P. Chamorro-Posada, J. Martín-Gil, P. Martín-Ramos, L.M. Navas-Gracia, Fundamentos de la Tecnología OLED (Fundamentals of OLED Technology). University of Valladolid, Spain (2008). ISBN 978-84-936644-0-4. Available online, with permission from the authors, at the webpage:
  • Kordt, Pascal; et al. (2015). "Modeling of Organic Light Emitting Diodes: From Molecular to Device Properties". Advanced Functional Materials 25 (13): 1955–1971.   Category:CS1 maint: Explicit use of et al.)
  • Shinar, Joseph (Ed.), Organic Light-Emitting Devices: A Survey. NY: Springer-Verlag (2004). ISBN 0-387-95343-4.
  • Hari Singh Nalwa (Ed.), Handbook of Luminescence, Display Materials and Devices, Volume 1–3. American Scientific Publishers, Los Angeles (2003). ISBN 1-58883-010-1. Volume 1: Organic Light-Emitting Diodes
  • Hari Singh Nalwa (Ed.), Handbook of Organic Electronics and Photonics, Volume 1–3. American Scientific Publishers, Los Angeles (2008). ISBN 1-58883-095-0.
  • Müllen, Klaus (Ed.), Organic Light Emitting Devices: Synthesis, Properties and Applications. Wiley-VCH (2006). ISBN 3-527-31218-8
  • Yersin, Hartmut (Ed.), Highly Efficient OLEDs with Phosphorescent Materials. Wiley-VCH (2007). ISBN 3-527-40594-1
  • Kho, Mu-Jeong, Javed, T., Mark, R., Maier, E., and David, C. (2008) 'Final Report: OLED Solid State Lighting - Kodak European Research' MOTI (Management of Technology and Innovation) Project, Judge Business School of the University of Cambridge and Kodak European Research, Final Report presented in 04 March 2008 at Kodak European Research at Cambridge Science Park, Cambridge, UK., pages 1-12.

Further reading

  1. ^ Kamtekar, K. T.; Monkman, A. P.; Bryce, M. R. (2010). "Recent Advances in White Organic Light-Emitting Materials and Devices (WOLEDs)". Advanced Materials 22 (5): 572–582.  
  2. ^ D'Andrade, B. W.; Forrest, S. R. (2004). "White Organic Light-Emitting Devices for Solid-State Lighting". Advanced Materials 16 (18): 1585–1595.  
  3. ^ Chang, Yi-Lu; Lu, Zheng-Hong (2013). "White Organic Light-Emitting Diodes for Solid-State Lighting". Journal of Display Technology PP (99): 1.  
  4. ^ Bernanose, A.; Comte, M.; Vouaux, P. (1953). "A new method of light emission by certain organic compounds". J. Chim. Phys. 50: 64. 
  5. ^ Bernanose, A.; Vouaux, P. (1953). "Organic electroluminescence type of emission". J. Chim. Phys. 50: 261. 
  6. ^ Bernanose, A. (1955). "The mechanism of organic electroluminescence". J. Chim. Phys. 52: 396. 
  7. ^ Bernanose, A. and Vouaux, P. (1955). J. Chim. Phys. 52: 509. 
  8. ^ Kallmann, H.;  
  9. ^ Kallmann, H.; Pope, M. (1960). "Bulk Conductivity in Organic Crystals". Nature 186 (4718): 31–33.  
  10. ^ Mark, Peter; Helfrich, Wolfgang (1962). "Space-Charge-Limited Currents in Organic Crystals". Journal of Applied Physics 33: 205.  
  11. ^ Pope, M.; Kallmann, H. P.; Magnante, P. (1963). "Electroluminescence in Organic Crystals". The Journal of Chemical Physics 38 (8): 2042.  
  12. ^ Sano, Mizuka; Pope, Martin; Kallmann, Hartmut (1965). "Electroluminescence and Band Gap in Anthracene". The Journal of Chemical Physics 43 (8): 2920.  
  13. ^ Helfrich, W.; Schneider, W. (1965). "Recombination Radiation in Anthracene Crystals". Physical Review Letters 14 (7): 229–231.  
  14. ^ Gurnee, E. and Fernandez, R. "Organic electroluminescent phosphors", U.S. Patent 3,172,862, Issue date: March 9, 1965
  15. ^ Partridge, Roger Hugh, "Radiation sources" U.S. Patent 3,995,299, Issue date: November 30, 1976
  16. ^ Partridge, R (1983). "Electroluminescence from polyvinylcarbazole films: 1. Carbazole cations". Polymer 24 (6): 733–738.  
  17. ^ Partridge, R (1983). "Electroluminescence from polyvinylcarbazole films: 2. Polyvinylcarbazole films containing antimony pentachloride". Polymer 24 (6): 739–747.  
  18. ^ Partridge, R (1983). "Electroluminescence from polyvinylcarbazole films: 3. Electroluminescent devices". Polymer 24 (6): 748–754.  
  19. ^ Partridge, R (1983). "Electroluminescence from polyvinylcarbazole films: 4. Electroluminescence using higher work function cathodes". Polymer 24 (6): 755–762.  
  20. ^ a b c Tang, C. W.; Vanslyke, S. A. (1987). "Organic electroluminescent diodes". Applied Physics Letters 51 (12): 913.  
  21. ^ a b Burroughes, J. H.; Bradley, D. D. C.; Brown, A. R.; Marks, R. N.; MacKay, K.; Friend, R. H.; Burns, P. L.; Holmes, A. B. (1990). "Light-emitting diodes based on conjugated polymers". Nature 347 (6293): 539–541.  
  22. ^ a b c Kho, Mu-Jeong, Javed, T., Mark, R., Maier, E., and David, C. (2008) Final Report: OLED Solid State Lighting - Kodak European Research, MOTI (Management of Technology and Innovation) Project, Judge Business School of the University of Cambridge and Kodak European Research, Final Report presented in 04 March 2008 at Kodak European Research at Cambridge Science Park, Cambridge, UK., pp. 1-12
  23. ^ Piromreun, Pongpun; Oh, Hwansool; Shen, Yulong; Malliaras, George G.; Scott, J. Campbell; Brock, Phil J. (2000). "Role of CsF on electron injection into a conjugated polymer". Applied Physics Letters 77 (15): 2403.  
  24. ^ D. Ammermann, A. Böhler, W. Kowalsky, Multilayer Organic Light Emitting Diodes for Flat Panel Displays, Institut für Hochfrequenztechnik, TU Braunschweig, 1995.
  25. ^ a b "Organic Light-Emitting Diodes Based on Graded Heterojunction Architecture Has Greater Quantum Efficiency". University of Minnesota. Retrieved 31 May 2011. 
  26. ^ Holmes, Russell; Erickson, N.; LüSsem, Björn; Leo, Karl (27 August 2010). "Highly efficient, single-layer organic light-emitting devices based on a graded-composition emissive layer". Applied Physics Letters 97: 083308.  
  27. ^ Lin Ke, Peng; Ramadas, K.; Burden, A.; Soo-Jin, C. (June 2006). "INdium-Tin-Oxide-Free Organic Light-Emitting Devices". Transactions on Electron Devices 53 (6): 1483–1486.  
  28. ^ Carter, S. A.; Angelopoulos, M.; Karg, S.; Brock, P. J.; Scott, J. C. (1997). "Polymeric anodes for improved polymer light-emitting diode performance". Applied Physics Letters 70 (16): 2067.  
  29. ^ Friend, R. H.; Gymer, R. W.; Holmes, A. B.; Burroughes, J. H.; Marks, R. N.; Taliani, C.; Bradley, D. D. C.; Santos, D. A. Dos; Brdas, J. L.; Lgdlund, M.; Salaneck, W. R. (1999). "Electroluminescence in conjugated polymers". Nature 397 (6715): 121–128.  
  30. ^ "Spintronic OLEDs could be brighter and more efficient". Engineer (Online Edition): 1. 16 July 2012. 
  31. ^ Davids, P. S.; Kogan, Sh. M.; Parker, I. D.; Smith, D. L. (1996). "Charge injection in organic light-emitting diodes: Tunneling into low mobility materials". Applied Physics Letters 69 (15): 2270.  
  32. ^ Crone, B. K.; Campbell, I. H.; Davids, P. S.; Smith, D. L. (1998). "Charge injection and transport in single-layer organic light-emitting diodes". Applied Physics Letters 73 (21): 3162.  
  33. ^ Crone, B. K.; Campbell, I. H.; Davids, P. S.; Smith, D. L.; Neef, C. J.; Ferraris, J. P. (1999). "Device physics of single layer organic light-emitting diodes". Journal of Applied Physics 86 (10): 5767.  
  34. ^ Bellmann, E.; Shaheen, S. E.; Thayumanavan, S.; Barlow, S.; Grubbs, R. H.; Marder, S. R.; Kippelen, B.; Peyghambarian, N. (1998). "New Triarylamine-Containing Polymers as Hole Transport Materials in Organic Light-Emitting Diodes: Effect of Polymer Structure and Cross-Linking on Device Characteristics". Chemistry of Materials 10 (6): 1668–1676.  
  35. ^ Sato, Y.; Ichinosawa, S.; Kanai, H. (1998). "Operation Characteristics and Degradation of Organic Electroluminescent Devices". IEEE Journal of Selected Topics in Quantum Electronics 4: 40–48.  
  36. ^  
  37. ^ Duarte, FJ (2007). "Coherent electrically excited organic semiconductors: visibility of interferograms and emission linewidth". Optics letters 32 (4): 412–4.  
  38. ^ Synopsis: A Single-Molecule Light-Emitting Diode, Physics, 28 January 2014
  39. ^ Researchers Develop First Single-Molecule LED, Photonics Online, 31 January 2014
  40. ^ 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.  
  41. ^ Bharathan, Jayesh; Yang, Yang (1998). "Polymer electroluminescent devices processed by inkjet printing: I. Polymer light-emitting logo". Applied Physics Letters 72 (21): 2660.  
  42. ^ Heeger, A. J. (1993) in W. R. Salaneck, I. Lundstrom, B. Ranby, Conjugated Polymers and Related Materials, Oxford, 27–62. ISBN 0-19-855729-9
  43. ^ Kiebooms, R.; Menon, R.; Lee, K. (2001) in H. S. Nalwa, Handbook of Advanced Electronic and Photonic Materials and Devices Volume 8, Academic Press, 1–86.
  44. ^ Wagaman, Michael; Grubbs, Robert H. (1997). "Synthesis of PNV Homo- and Copolymers by a ROMP Precursor Route". Synthetic Metals 84 (1–3): 327–328.  
  45. ^ Wagaman, Michael; Grubbs, Robert H. (1997). "Synthesis of Organic and Water Soluble Poly(1,4-phenylenevinylenes) Containing Carboxyl Groups: Living Ring-Opening Metathesis Polymerization (ROMP) of 2,3-Dicarboxybarrelenes". Macromolecules 30 (14): 3978–3985.  
  46. ^ Pu, Lin; Wagaman, Michael; Grubbs, Robert H. (1996). "Synthesis of Poly(1,4-naphthylenevinylenes): Metathesis Polymerization of Benzobarrelenes". Macromolecules 29 (4): 1138–1143.  
  47. ^ Fallahi, Afsoon; Alahbakhshi, Masoud; Mohajerani, Ezeddin; Afshar Taromi, Faramarz; Mohebbi, Alireza; Shahinpoor, Mohsen (2015). "Cationic Water-Soluble Conjugated Polyelectrolytes/Graphene Oxide Nanocomposites as Efficient Green Hole Injection Layers in Organic Light Emitting Diodes". The Journal of Physical Chemistry C 119 (23): 13144.  
  48. ^ a b Yang, Xiaohui; Neher, Dieter; Hertel, Dirk; Daubler, Thomas (2004). "Highly Efficient Single-Layer Polymer Electrophosphorescent Devices". Advanced Materials 16 (2): 161–166.  
  49. ^ a b Baldo, M. A.; O'Brien, D. F.; You, Y.; Shoustikov, A.; Sibley, S.; Thompson, M. E.; Forrest, S.R. (1998). "Highly Efficient phosphorescent emission from organic electroluminescent devices". Nature 395 (6698): 151–154.  
  50. ^ a b Baldo, M. A.; Lamansky, S.; Burrows, P. E.; Thompson, M. E.; Forrest, S. R. (1999). "Very high-efficiency green organic light-emitting devices based on electrophosphorescence". Applied Physics Letters 75: 4.  
  51. ^ Adachi, C.; Baldo, M. A.; Thompson, M. E.; Forrest, S. R. (2001). "Nearly 100% internal phosphorescence efficiency in an organic light-emitting device". Journal of Applied Physics 90 (10): 5048.  
  52. ^ Singh, Madhusudan; Chae, Hyun Sik; Froehlich, Jesse D.; Kondou, Takashi; Li, Sheng; Mochizuki, Amane; Jabbour, Ghassan E. (2009). "Electroluminescence from printed stellate polyhedral oligomeric silsesquioxanes". Soft Matter 5 (16): 3002.  
  53. ^ Bardsley, J. N. (2004). "International OLED Technology Roadmap". IEEE Journal of Selected Topics in Quantum Electronics 10: 3–4.  
  54. ^ US 5986401, Mark E. Thompson, Stephen R. Forrest, Paul Burrows, "High contrast transparent organic light emitting device display", published 1999-11-16 
  55. ^ Chu, Ta-Ya; Chen, Jenn-Fang; Chen, Szu-Yi; Chen, Chao-Jung; Chen, Chin H. (2006). "Highly efficient and stable inverted bottom-emission organic light emitting devices". Applied Physics Letters 89 (5): 053503.  
  56. ^ Liu, Jie; Lewis, Larry N.; Duggal, Anil R. (2007). "Photoactivated and patternable charge transport materials and their use in organic light-emitting devices". Applied Physics Letters 90 (23): 233503.  
  57. ^ Boroson, Michael; Tutt, Lee; Nguyen, Kelvin; Preuss, Don; Culver, Myron; Phelan, Giana (2005). "16.5L: Late-News-Paper: Non-Contact OLED Color Patterning by Radiation-Induced Sublimation Transfer (RIST)". SID Symposium Digest of Technical Papers 36: 972.  
  58. ^ Grimaldi, I. A.; De Girolamo Del Mauro, A.; Nenna, G.; Loffredo, F.; Minarini, C.; Villani, F.; d’Amore, A.; Acierno, D.; Grassia, L. (2010). "Inkjet Etching of Polymer Surfaces to Manufacture Microstructures for OLED Applications". AIP Conference Proceedings. p. 104.  
  59. ^ Sasaoka, Tatsuya; Sekiya, Mitsunobu; Yumoto, Akira; Yamada, Jiro; Hirano, Takashi; Iwase, Yuichi; Yamada, Takao; Ishibashi, Tadashi; Mori, Takao; Asano, Mitsuru; Tamura, Shinichiro; Urabe, Tetsuo (2001). "24.4L: Late-News Paper: A 13.0-inch AM-OLED Display with Top Emitting Structure and Adaptive Current Mode Programmed Pixel Circuit (TAC)". SID Symposium Digest of Technical Papers 32: 384.  
  60. ^ Tsujimura, T.; Kobayashi, Y.; Murayama, K.; Tanaka, A.; Morooka, M.; Fukumoto, E.; Fujimoto, H.; Sekine, J.; Kanoh, K.; Takeda, K.; Miwa, K.; Asano, M.; Ikeda, N.; Kohara, S.; Ono, S.; Chung, C. T.; Chen, R. M.; Chung, J. W.; Huang, C. W.; Guo, H. R.; Yang, C. C.; Hsu, C. C.; Huang, H. J.; Riess, W.; Riel, H.; Karg, S.; Beierlein, T.; Gundlach, D.; Alvarado, S.; et al. (2003). "4.1: A 20-inch OLED Display Driven by Super-Amorphous-Silicon Technology". SID Symposium Digest of Technical Papers 34: 6.  
  61. ^ Bower, C. A.; Menard, E.; Bonafede, S.; Hamer, J. W.; Cok, R. S. (2011). "Transfer-Printed Microscale Integrated Circuits for High Performance Display Backplanes". IEEE Transactions on Components, Packaging and Manufacturing Technology 1 (12): 1916.  
  62. ^ Pardo, Dino A.; Jabbour, G. E.; Peyghambarian, N. (2000). "Application of Screen Printing in the Fabrication of Organic Light-Emitting Devices". Advanced Materials 12 (17): 1249–1252.  
  63. ^ 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): 477–479.  
  64. ^ "Comparison of OLED and LCD". Fraunhofer IAP: OLED Research. 2008-11-18. Archived from the original on February 4, 2010. Retrieved 2010-01-25. 
  65. ^ Wong, William (16 December 2004). "Firefox: A Browser For Embedded Applications". Electronic Design 52 (28): 25. 
  66. ^ Zhang, Mingxiao; Chen, Z.; Xiao, L.; Qu, B.; Gong, Q. (18 March 2013). "Optical design for improving optical properties of top-emitting organic light emitting diodes". Journal of Applied Physics 113 (11): 113105.  
  67. ^ "LG 55EM9700". 2013-01-02. Retrieved 2015-01-14. 
  68. ^ "Why Do Some OLEDs Have Motion Blur?". Blur Busters Blog (based on Microsoft Research work). 2013-04-15. Retrieved 2013-04-18. 
  69. ^ "OLED TV estimated lifespan shorter then expected". HDTV Info Europe. (2008-05-08).
  70. ^ HP Monitor manual. CCFL-Backlit LCD. Page 32. Retrieved 2011-10-04.
  71. ^ Viewsonic Monitor manual. LED-Backlit LCD. Retrieved 2011-10-04.
  72. ^ Kondakov, D; Lenhart, W.; Nochols, W. (2007). "Operational degradation of organic light-emitting diodes: Mechanism and identification of chemical products". Journal of Applied Physics 101 (2): 1.  
  73. ^ "OLED lifespan doubled?" HDTV Info Europe. (2008-01-25).
  74. ^ Toshiba and Panasonic double lifespan of OLED, January 25, 2008, Toshiba and Panasonic double lifespan of OLED
  75. ^ Cambridge Display Technology, Cambridge Display Technology and Sumation Announce Strong Lifetime Improvements to P-OLED (Polymer OLED) Material; Blue P-OLED Materials Hit 10,000 Hour Lifetime Milestone at 1,000 cd/sq.m, March 26, 2007. Retrieved January 11, 2011.
  76. ^ "Ageless OLED". Retrieved 2009-11-16. 
  77. ^ Fallahi, Afsoon; Afshar Taromi, Faramarz; Mohebbi, Alireza; D. Yuen, Jonathan; Shahinpoor, Mohsen (2014). "A novel ambipolar polymer: from organic thin-film transistors to enhanced air-stable blue light emitting diodes". Journal of Materials Chemistry C 2: 6491. 
  78. ^ Shen, Jiun Yi; Lee, Chung Ying; Huang, Tai-Hsiang; Lin, Jiann T.; Tao, Yu-Tai; Chien, Chin-Hsiung; Tsai, Chiitang (2005). "High Tg blue emitting materials for electroluminescent devices". Journal of Materials Chemistry (free text) 15 (25): 2455.  
  79. ^ Kim, Seul Ong; Lee, Kum Hee; Kim, Gu Young; Seo, Ji Hoon; Kim, Young Kwan; Yoon, Seung Soo (2010). "A highly efficient deep blue fluorescent OLED based on diphenylaminofluorenylstyrene-containing emitting materials". Synthetic Metals 160 (11–12): 1259–1265.  
  80. ^ Jabbour, G. E.; Kawabe, Y.; Shaheen, S. E.; Wang, J. F.; Morrell, M. M.; Kippelen, B.; Peyghambarian, N. (1997). "Highly efficient and bright organic electroluminescent devices with an aluminum cathode". Applied Physics Letters 71 (13): 1762.  
  81. ^ Mikami, Akiyoshi; Koshiyama, Tatsuya; Tsubokawa, Tetsuro (2005). "High-Efficiency Color and White Organic Light-Emitting Devices Prepared on Flexible Plastic Substrates". Japanese Journal of Applied Physics 44: 608–612.  
  82. ^ Mikami, Akiyoshi; Nishita, Yusuke; Iida, Yoichi (2006). "35-3: High Efficiency Phosphorescent Organic Light-Emitting Devices Coupled with Lateral Color-Conversion Layer". SID Symposium Digest of Technical Papers 37: 1376.  
  83. ^ "OLED Sealing Process Reduces Water Intrusion and Increases Lifetime". Georgia Tech Research News. 2008-04-23. 
  84. ^ DisplayMate: the GS5 display is the best mobile display ever, outperforming all previous OLED and LCD panels | OLED-Info
  85. ^ Stokes, Jon. (2009-08-11) This September, OLED no longer "three to five years away". Retrieved 2011-10-04.
  86. ^ Michael Kanellos, "Start-up creates flexible sheets of light", CNet, December 6, 2007. Retrieved 20 July 2008.
  87. ^ "Philips Lumiblades". 2009-08-09. Retrieved 2009-08-17. 
  88. ^ Session Border Controller. (2011-09-13). Retrieved 2012-11-12.
  89. ^ Universal Display Corporation (UDC) | OLED-Info
  90. ^ Electronic News, OLEDs Replacing LCDs in Mobile Phones, April 7, 2005. Retrieved July 28, 2007.
  91. ^ "HTC ditches Samsung AMOLED display for Sony's Super LCDs". International Business Times. 2010-07-26. Retrieved 2010-07-30. 
  92. ^ "Google Nexus S to feature Super Clear LCD in Russia (and likely in other countries, too)". 2010-12-07. Retrieved 2010-12-08. 
  93. ^ "ANWELL: Higher profit, higher margins going forward". 2007-08-15. 
  94. ^ "AUO". 2012-02-21. 
  95. ^ "Chi Mei EL (CMEL)". 
  96. ^ "LG OLEDs". 
  97. ^ "OLED companies". 
  98. ^ Rawlings, John (2010-08-07). "OLED Shearwater Predator Dive Computer Review". AtlasOmega Media. Retrieved 2013-04-10. 
  99. ^ Tourish, Jeff. "Shearwater Predator CCR Computer". Advanced Diver Magazine. Retrieved 2013-04-10. 
  100. ^ "DuPont Creates 50" OLED in Under 2 Minutes". Retrieved 2010-06-10. 
  101. ^ "DuPont Delivers OLED Technology Scalable for Television". 2010-05-12. Retrieved 2010-05-12. 
  102. ^, Kodak Signs OLED Cross-License Agreement. Retrieved March 14, 2008.
  103. ^ Bendable smartphones aren't coming anytime soon, The Sydney Morning Herald, Ian King, 16 December 2013
  104. ^ Samsung to accelerate flexible OLED development | OLED-Info
  105. ^ Cherenack, Kunigunde; Van Os, K.; Pieterson, L. (April 2012). "Smart photonic textiles begin to weave their magic". Laser Focus World 48 (4): 63. 
  106. ^ "Samsung SDI – The world's largest OLED display maker". Retrieved 2009-08-17. 
  107. ^ "Samsung, LG in legal fight over brain drain". The Korea Times. 2010-07-17. Retrieved 2010-07-30. 
  108. ^ a b "Frost & Sullivan Recognizes Samsung SDI for Market Leadership in the OLED Display Market | Find Articles at BNET". 2008-07-17. Retrieved 2009-08-17. 
  109. ^ "World's Largest 21-inch OLED for TVs from Samsung". 2005-01-04. Retrieved 2009-08-17. 
  110. ^ Robischon, Noah (2008-01-09). "Samsung's 31-Inch OLED Is Biggest, Thinnest Yet – AM-OLED". Gizmodo. Retrieved 2009-08-17. 
  111. ^ Ricker, Thomas (2008-05-16). "Samsung's 12.1-inch OLED laptop concept makes us swoon". Engadget. Retrieved 2009-08-17. 
  112. ^ "Samsung: OLED Notebooks In 2010". Laptop News. TrustedReviews. Retrieved 2009-08-17. 
  113. ^ a b Takuya Otani, Nikkei Electronics (2008-10-29). "[FPDI] Samsung Unveils 0.05mm 'Flapping' OLED Panel – Tech-On!". Retrieved 2009-08-17. 
  114. ^ "40-inch OLED panel from Samsung". (2008-10-30)
  115. ^ "Samsung presents world's first and largest transparent OLED laptop at CES". 2010-01-07. Archived from the original on January 11, 2010. 
  116. ^ "CES: Samsung shows OLED display in a photo card". 2010-01-07. 
  117. ^ "Samsung Super AMOLED Plus display announced". Retrieved 2011-01-06. 
  118. ^ Clark, Shaylin (2012-01-12). CES 2012: Samsung’s OLED TV Rakes In Awards. WebProNews. Retrieved 2012-12-03.
  119. ^ Rougeau, Michael (2013-01-08). Samsung's curved OLED TV provides an 'IMAX-like' experience. Techradar. Retrieved 2013-01-08.
  120. ^ Boylan, Chris (2013-08-13). "Bring Out Your OLED: Samsung KN55S9C OLED TV Available Now for $8999.99". Big Picture Big Sound. Retrieved 2013-08-13.
  121. ^ Alex Lane (6 September 2013). "John Lewis TV Gallery video: 4K and OLED from Samsung, Sony, LG and Panasonic". Recombu. Retrieved 26 September 2013. 
  122. ^ Sam Byford (8 October 2013). "Samsung's Galaxy Round is the first phone with a curved display". The Verge. Vox Media, Inc. Retrieved 10 November 2013. 
  123. ^ a b Sony XEL-1:The world's first OLED TV, (2008-11-17).
  124. ^ "Sony's Clie PEG-VZ90—the world's most expensive Palm?". Engadget. 2004-09-14. Retrieved 2010-07-30. 
  125. ^ "MD Community Page: Sony MZ-RH1". 2007-02-24. Retrieved 2009-08-17. 
  126. ^ "Sony NWZ-X1000-series OLED Walkman specs released". Slashgear. 2009-03-09. Retrieved 2011-01-01. 
  127. ^ "Sony announces a 27-inch OLED TV". HDTV Info Europe (2008-05-29)
  128. ^ CNET News, Sony to sell 11-inch OLED TV this year, April 12, 2007. Retrieved July 28, 2007.
  129. ^ The Sony Drive XEL-1 OLED TV: 1,000,000:1 contrast starting December 1st, Engadget (2007-10-01).
  130. ^ "Sony claims development of world's first flexible, full-color OLED display". Gizmo Watch. 2007-05-25. Retrieved 2010-07-30. 
  131. ^ Sony's 3.5- and 11-inch OLEDs are just 0.008- and 0.012-inches thin. Engadget (2008-04-16). Retrieved 2011-10-04.
  132. ^ (Display 2008)開幕。ソニーの0.3mm有機ELパネルなど-150型プラズマやビクターの3D技術など. (2008-04-16)
  133. ^ Japanese firms team up on energy-saving OLED panels, AFP (2008-07-10).
  134. ^ Athowon, Desire (2008). "Sony Working on Bendable, Folding OLED Screens". 
  135. ^ "Sony OLED 3D TV eyes-on". Engadget. Retrieved 2010-01-11. 
  136. ^ Snider, Mike (2011-01-28). "Sony unveils NGP, its new portable gaming device". USA Today. Retrieved 2011-01-27. 
  137. ^ "Sony Professional Reference Monitor". Sony. Retrieved 2011-02-17. 
  138. ^ "Sony, Panasonic tying up in advanced TV displays". June 25, 2012. 
  139. ^ LG 15EL9500 OLED Television. Retrieved 2011-10-04.
  140. ^ LG announces 31" OLED 3DTV. (2010-09-03). Retrieved 2011-10-04.
  141. ^ LG's 55-inch 'world's largest' OLED HDTV panel is official, coming to CES 2012. Engadget (2011-12-25). Retrieved 2012-11-12.
  142. ^ OLED TV. LG (2010-09-03). Retrieved 2012-12-21.
  143. ^ "OLED TV: Best. Picture. Ever.".  
  144. ^ Summary of UNIVERSAL DISPLAY CORP \PA\ - Yahoo! Finance
  145. ^ MITSUBISHI ELECTRIC News Releases Installs 6-Meter OLED Globe at Science Museum. (2011-06-01). Retrieved 2012-11-12.
  146. ^ Coxworth, Ben (2011-03-31). Video Name Tags turn salespeople into walking TV commercials. Retrieved 2012-11-12.
  147. ^ Three Minutes of Video Every Broadcaster and Advertiser MUST SEE.avi – CBS Videos : Firstpost Topic – Page 1. (2012-08-10). Retrieved 2012-11-12.
  148. ^ BMW wants to put super-efficient OLED tail lights on your next car, Engadget, 10 April 2014, Jon Fingas
  149. ^ Japanese company doubles diode panel's life span, Global Post, 13 October 2014
  150. ^ From Molecules to Organic Light Emitting Diodes, Max Planck Institute for Polymer Research, 7 April 2015.
  151. ^ Kordt, Pascal; et al. (2015). "Modeling of Organic Light Emitting Diodes: From Molecular to Device Properties". Advanced Functional Materials 25 (13): 1955–1971.  


See also

The search for efficient OLED materials has been extensively supported by simulation methods. By now it is possible to calculate important properties completely computationally, independent of experimental input.[150][151] This allows cost-efficient pre-screening of materials, prior to expensive synthesis and experimental characterisation.

[149] In 2014,


BMW plans to use OLEDs in tail lights and interior lights in their future cars; however, OLEDs are currently too dim to be used for brake lights, headlights and indicators.[148]


On January 6, 2011, Los Angeles based technology company Recom Group introduced the first small screen consumer application of the OLED at the Consumer Electronics Show in Las Vegas. This was a 2.8" (7 cm) OLED display being used as a wearable video name tag.[146] At the Consumer Electronics Show in 2012, Recom Group introduced the world's first video mic flag incorporating three 2.8" (7 cm) OLED displays on a standard broadcaster's mic flag. The video mic flag allowed video content and advertising to be shown on a broadcasters standard mic flag.[147]

Recom Group/video name tag applications

Lumiotec is the first company in the world developing and selling, since January 2011, mass-produced OLED lighting panels with such brightness and long lifetime. Lumiotec is a joint venture of Mitsubishi Heavy Industries, ROHM, Toppan Printing, and Mitsui & Co. On June 1, 2011, Mitsubishi installed a 6-meter OLED 'sphere' in Tokyo's Science Museum.[145]

Mitsubishi applications

In January 2015, LG Display signed a long term agreement with Universal Display Corporation for the supply of OLED materials and the right to use their patented OLED emitters.[144]

CNET reviewed the LG 55EC9300 OLED Television in September 2014 and called it the "Best. Picture. Ever." offering better picture quality than LED TV and Plasma TV and without their disadvantages.[143]

As of 2010, LG Electronics produced one model of OLED television, the 15 inch 15EL9500[139] and had announced a 31" (78 cm) OLED 3D television for March 2011.[140] On December 26, 2011, LG officially announced the "world's largest 55" OLED panel" and featured it at CES 2012.[141] In late 2012, LG announces the launch of the 55EM9600 OLED television in Australia.[142]

LG applications

On June 25, 2012, Sony and Panasonic announced a joint venture for creating low cost mass production OLED televisions by 2013.[138]

On February 17, 2011, Sony announced its 25" (63.5 cm) OLED Professional Reference Monitor aimed at the Cinema and high end Drama Post Production market.[137]

In January 2011, Sony announced the PlayStation Vita handheld game console (the successor to the PSP) will feature a 5-inch OLED screen.[136]

Sony exhibited a 24.5" (62 cm) prototype OLED 3D television during the Consumer Electronics Show in January 2010.[135]

In October 2008, Sony published results of research it carried out with the Max Planck Institute over the possibility of mass-market bending displays, which could replace rigid LCDs and plasma screens. Eventually, bendable, see-through displays could be stacked to produce 3D images with much greater contrast ratios and viewing angles than existing products.[134]

In July 2008, a Japanese government body said it would fund a joint project of leading firms, which is to develop a key technology to produce large, energy-saving organic displays. The project involves one laboratory and 10 companies including Sony Corp. NEDO said the project was aimed at developing a core technology to mass-produce 40 inch or larger OLED displays in the late 2010s.[133]

In May 2007, Sony publicly unveiled a video of a 2.5-inch flexible OLED screen which is only 0.3 millimeters thick.[130] At the Display 2008 exhibition, Sony demonstrated a 0.2 mm thick 3.5 inch (9 cm) display with a resolution of 320×200 pixels and a 0.3 mm thick 11 inch (28 cm) display with 960×540 pixels resolution, one-tenth the thickness of the XEL-1.[131][132]

At the 2007 Las Vegas Consumer Electronics Show (CES), Sony showcased 11-inch (28 cm, resolution 960×540) and 27-inch (68.5 cm), full HD resolution at 1920 × 1080 OLED TV models.[127] Both claimed 1,000,000:1 contrast ratios and total thicknesses (including bezels) of 5 mm. In April 2007, Sony announced it would manufacture 1000 11-inch (28 cm) OLED TVs per month for market testing purposes.[128] On October 1, 2007, Sony announced that the 11-inch (28 cm) model, now called the XEL-1, would be released commercially;[123] the XEL-1 was first released in Japan in December 2007.[129]

The Sony CLIÉ PEG-VZ90 was released in 2004, being the first PDA to feature an OLED screen.[124] Other Sony products to feature OLED screens include the MZ-RH1 portable minidisc recorder, released in 2006[125] and the Walkman X Series.[126]

Sony XEL-1, the world's first OLED TV.[123] (front)

Sony applications

Samsung introduced the Galaxy Round smartphone in the Korean market in October 2013. The device features a 1080p screen, measuring 5.7 inches (14 cm), that curves on the vertical axis in a rounded case. The corporation has promoted the following advantages: A new feature called "Round Interaction" that allows users to look at information by tilting the handset on a flat surface with the screen off, and the feel of one continuous transition when the user switches between home screens.[122]

On September 6, 2013, Samsung launched its 55-inch curved OLED TV (model KE55S9C) in the United Kingdom with John Lewis.[121]

On August 13, 2013, Samsung announced availability of a 55-inch curved OLED TV (model KN55S9C) in the US at a price point of $8999.99.[120]

On January 8, 2013, at CES Samsung unveiled a unique curved 4K Ultra S9 OLED television, which they state provides an "IMAX-like experience" for viewers.[119]

At CES 2012, Samsung introduced the first 55" TV screen that uses Super OLED technology.[118]

Samsung's latest AMOLED smartphones use their Super AMOLED trademark, with the Samsung Wave S8500 and Samsung i9000 Galaxy S being launched in June 2010. In January 2011 Samsung announced their Super AMOLED Plus displays, which offer several advances over the older Super AMOLED displays: real stripe matrix (50% more sub pixels), thinner form factor, brighter image and an 18% reduction in energy consumption.[117]

At the Consumer Electronics Show (CES) in January 2010, Samsung demonstrated a laptop computer with a large, transparent OLED display featuring up to 40% transparency[115] and an animated OLED display in a photo ID card.[116]

In the same month, Samsung unveiled what was then the world's largest OLED Television at 40-inch with a Full HD resolution of 1920 × 1080 pixels.[114] In the FPD International, Samsung stated that its 40-inch OLED Panel is the largest size currently possible. The panel has a contrast ratio of 1,000,000:1, a colour gamut of 107% NTSC, and a luminance of 200 cd/m2 (peak luminance of 600 cd/m2).

In October 2008, Samsung showcased the world's thinnest OLED display, also the first to be "flappable" and bendable.[113] It measures just 0.05 mm (thinner than paper), yet a Samsung staff member said that it is "technically possible to make the panel thinner".[113] To achieve this thickness, Samsung etched an OLED panel that uses a normal glass substrate. The drive circuit was formed by low-temperature polysilicon TFTs. Also, low-molecular organic EL materials were employed. The pixel count of the display is 480 × 272. The contrast ratio is 100,000:1, and the luminance is 200 cd/m2. The colour reproduction range is 100% of the NTSC standard.

In May 2008, Samsung unveiled an ultra-thin 12.1 inch (30 cm) laptop OLED display concept, with a 1,280×768 resolution with infinite contrast ratio.[111] According to Woo Jong Lee, Vice President of the Mobile Display Marketing Team at Samsung SDI, the company expected OLED displays to be used in notebook PCs as soon as 2010.[112]

Samsung SDI announced in 2005 the world's largest OLED TV at the time, at 21 inches (53 cm).[109] This OLED featured the highest resolution at the time, of 6.22 million pixels. In addition, the company adopted active matrix based technology for its low power consumption and high-resolution qualities. This was exceeded in January 2008, when Samsung showcased the world's largest and thinnest OLED TV at the time, at 31 inches (78 cm) and 4.3 mm.[110]

By 2004 Samsung, South Korea's largest conglomerate, was the world's largest OLED manufacturer, producing 40% of the OLED displays made in the world,[106] and as of 2010 has a 98% share of the global AMOLED market.[107] The company is leading the world of OLED industry, generating $100.2 million out of the total $475 million revenues in the global OLED market in 2006.[108] As of 2006, it held more than 600 American patents and more than 2800 international patents, making it the largest owner of AMOLED technology patents.[108]

Samsung applications

Textiles incorporating OLEDs are an innovation in the fashion world and pose for a way to integrate lighting to bring inert objects to a whole new level of fashion. The hope is to combine the comfort and low cost properties of textile with the OLEDs properties of illumination and low energy consumption. Although this scenario of illuminated clothing is highly plausible, challenges are still a road block. Some issues include: the lifetime of the OLED, rigidness of flexible foil substrates, and the lack of research in making more fabric like photonic textiles.[105]


A technical writer at the Sydney Herald thinks foldable OLED smartphones could be as much as a decade away because of the cost of producing them. There is a relatively high failure rate when producing these screens. As little as a speck of dust can ruin a screen during production. Creating a battery that can be folded is another hurdle.[103] However, Samsung have accelerated their plans to release a foldable display by the end of 2015[104]

RIM, the maker of BlackBerry smartphones, use OLED displays in their BlackBerry 10 devices.

The use of OLEDs may be subject to patents held by Universal Display Corporation, Eastman Kodak, DuPont, General Electric, Royal Philips Electronics, numerous universities and others.[102] There are by now thousands of patents associated with OLEDs, both from larger corporations and smaller technology companies.[22]

DuPont stated in a press release in May 2010 that they can produce a 50-inch OLED TV in two minutes with a new printing technology. If this can be scaled up in terms of manufacturing, then the total cost of OLED TVs would be greatly reduced. DuPont also states that OLED TVs made with this less expensive technology can last up to 15 years if left on for a normal eight-hour day.[100][101]

In 2009, Shearwater Research introduced the Predator as the first color OLED diving computer available with a user replaceable battery.[98][99]

Other manufacturers of OLED panels include Anwell Technologies Limited (Hong Kong),[93] AU Optronics (Taiwan),[94] Chimei Innolux Corporation (Taiwan),[95] LG (Korea),[96] and others.[97]

OLED displays were used in watches made by Fossil (JR-9465) and Diesel (DZ-7086).

The Google and HTC Nexus One smartphone includes an AMOLED screen, as does HTC's own Desire and Legend phones. However, due to supply shortages of the Samsung-produced displays, certain HTC models will use Sony's SLCD displays in the future,[91] while the Google and Samsung Nexus S smartphone will use "Super Clear LCD" instead in some countries.[92]

OLEDs have been used in most Motorola and Samsung color cell phones, as well as some HTC, LG and Sony Ericsson models.[90] Nokia has also introduced some OLED products including the N85 and the N86 8MP, both of which feature an AMOLED display. OLED technology can also be found in digital media players such as the Creative ZEN V, the iriver clix, the Zune HD and the Sony Walkman X Series.

Universal Display Corporation (UDC) currently owns or has exclusive, co-exclusive or sole license rights to more than 3,000 issued and pending patents worldwide for the commercialization of phosphorescent based OLEDs and also flexible, transparent and stacked OLEDs – for both display and lighting applications. Its phosphorescent OLED technologies and materials are licensed and supplied to companies such as Samsung, LG, AU Optronics CMEL, Pioneer, Panasonic Idemitsu OLED lighting and Konica Minolta. Back in 2009 UDC claimed that "virtually all AMOLEDs on the market use our technology".[89]

[88] based in Dresden, Germany, introduced a line of OLED desk lamps called "Victory" in September, 2011.Novaled AG and [87] Lighting have made OLED lighting samples under the brand name "Lumiblade" available onlinePhilips [86] OLED technology is used in commercial applications such as displays for mobile phones and portable

OLED lighting in a shopping mall in Aachen, Germany
A 3.8 cm (1.5 in) OLED display from a Creative ZEN V media player
Magnified image of the AMOLED screen on the Google Nexus One smartphone using the RGBG system of the PenTile Matrix Family.

Manufacturers and commercial uses

The biggest technical problem for OLEDs was the limited lifetime of the organic materials. One 2008 technical report on an OLED TV panel found that "After 1,000 hours the blue luminance degraded by 12%, the red by 7% and the green by 8%."[69] In particular, blue OLEDs historically have had a lifetime of around 14,000 hours to half original brightness (five years at 8 hours a day) when used for flat-panel displays. This is lower than the typical lifetime of LCD, LED or PDP technology. Each currently is rated for about 25,000–40,000 hours to half brightness, depending on manufacturer and model.[70][71] Degradation occurs because of the accumulation of nonradiative recombination centers and luminescence quenchers in the emissive zone. It is said that the chemical breakdown in the semiconductors occurs in four steps: 1) recombination of charge carriers through the absorption of UV light, 2) homolytic dissociation, 3) subsequent radical addition reactions that form π radicals, and 4) disproportionation between two radicals resulting in hydrogen-atom transfer reactions.[72] However, some manufacturers' displays aim to increase the lifespan of OLED displays, pushing their expected life past that of LCD displays by improving light outcoupling, thus achieving the same brightness at a lower drive current.[73][74] In 2007, experimental OLEDs were created which can sustain 400 cd/m2 of luminance for over 198,000 hours for green OLEDs and 62,000 hours for blue OLEDs.[75]
Color balance
Additionally, as the OLED material used to produce blue light degrades significantly more rapidly than the materials that produce other colors, blue light output will decrease relative to the other colors of light. This variation in the differential color output will change the color balance of the display and is much more noticeable than a decrease in overall luminance.[76] This can be avoided partially by adjusting color balance, but this may require advanced control circuits and interaction with the user, which is unacceptable for users. More commonly, though, manufacturers optimize the size of the R, G and B subpixels to reduce the current density through the subpixel in order to equalize lifetime at full luminance. For example, a blue subpixel may be 100% larger than the green subpixel. The red subpixel may be 10% smaller than the green.
Efficiency of blue OLEDs
Improvements to the efficiency and lifetime of blue OLEDs is vital to the success of OLEDs as replacements for LCD technology. Considerable research has been invested in developing blue OLEDs with high external quantum efficiency as well as a deeper blue color.[77][78][79] External quantum efficiency values of 20% and 19% have been reported for red (625 nm) and green (530 nm) diodes, respectively.[80][81] However, blue diodes (430 nm) have only been able to achieve maximum external quantum efficiencies in the range of 4% to 6%.[82]
Water damage
Water can instantly damage the organic materials of the displays. Therefore, improved sealing processes are important for practical manufacturing. Water damage especially may limit the longevity of more flexible displays.[83]
Outdoor performance
As an emissive display technology, OLEDs rely completely upon converting electricity to light, unlike most LCDs which are to some extent reflective. e-paper leads the way in efficiency with ~ 33% ambient light reflectivity, enabling the display to be used without any internal light source. The metallic cathode in an OLED acts as a mirror, with reflectance approaching 80%, leading to poor readability in bright ambient light such as outdoors. However, with the proper application of a circular polarizer and antireflective coatings, the diffuse reflectance can be reduced to less than 0.1%. With 10,000 fc incident illumination (typical test condition for simulating outdoor illumination), that yields an approximate photopic contrast of 5:1. Recent advances in OLED technologies, however, enable OLEDs to become actually better than LCDs in bright sunlight. The Super AMOLED display in the Galaxy S5, for example, was found to outperform all LCD displays on the market in terms of brightness and reflectance.[84]
Power consumption
While an OLED will consume around 40% of the power of an LCD displaying an image that is primarily black, for the majority of images it will consume 60–80% of the power of an LCD. However, an OLED can use more than three times as much power to display an image with a white background, such as a document or web site.[85] This can lead to reduced battery life in mobile devices, when white backgrounds are used.
An old OLED display showing wear
LEP (light emitting polymer) display showing partial failure


Lower cost in the future
OLEDs can be printed onto any suitable registration, lining up the different printed layers to the required degree of accuracy.
Lightweight and flexible plastic substrates
OLED displays can be fabricated on flexible plastic substrates leading to the possible fabrication of roll-up displays embedded in fabrics or clothing. As the substrate used can be flexible such as polyethylene terephthalate (PET),[63] the displays may be produced inexpensively. Further, plastic substrates are shatter resistant, unlike glass displays used in LCD devices.
Wider viewing angles and improved brightness
OLEDs can enable a greater artificial contrast ratio (both dynamic range and static, measured in purely dark conditions) and a wider viewing angle compared to LCDs because OLED pixels emit light directly. OLED pixel colors appear correct and unshifted, even as the viewing angle approaches 90° from normal.
Better power efficiency and thickness
LCDs filter the light emitted from a backlight, allowing a small fraction of light through. So, they cannot show true black. However, an inactive OLED element does not produce light or consume power, thus allowing true blacks.[64] Dismissing the backlight also makes OLEDs lighter because some substrates are not needed. This allows electronics potentially to be manufactured more cheaply, but, first, a larger production scale is needed, because OLEDs still somewhat are niche products.[65] When looking at top-emitting OLEDs, thickness also plays a role when talking about index match layers (IMLs). Emission intensity is enhanced when the IML thickness is 1.3–2.5 nm. The refractive value and the matching of the optical IMLs property, including the device structure parameters, also enhance the emission intensity at these thicknesses.[66]
Response time
OLEDs also have a much faster response time than an LCD. Using response time compensation technologies, the fastest modern LCDs can reach as low as 1 ms response times for their fastest color transition and are capable of refresh frequencies as high as 144 Hz. OLED response times are up to 1,000 times faster than LCD according to LG,[67] putting conservative estimates at under 10 μs (0.01 ms), which in theory could accommodate refresh frequencies approaching 100 kHz (100,000 Hz). Due to their extremely fast response time, OLED displays can also be easily designed to interpolate black frames, creating an effect similar to CRT flicker in order to avoid the sample-and-hold behavior used on both LCDs and some OLED displays that creates the perception of motion blur.[68]

The different manufacturing process of OLEDs lends itself to several advantages over flat panel displays made with LCD technology.

Demonstration of a 4.1" prototype flexible display from Sony


Transfer-printing is an emerging technology to assemble large numbers of parallel OLED and AMOLED devices efficiently. It takes advantage of standard metal deposition, photolithography, and etching to create alignment marks commonly glass, or other device substrates. Thin polymer adhesive layers are applied to enhance resistance to particles and surface defects. Microscale ICs are transfer-printed onto the adhesive surface and then baked to fully cure adhesive layers. An additional photosensitive polymer layer is applied to the substrate to account for the topography caused by the printed ICs, reintroducing a flat surface. Photolithography and etching removes some polymer layers to uncover conductive pads on the ICs. Afterwards, the anode layer is applied to the device backplane to form bottom electrode. OLED layers are applied to the anode layer with conventional vapor deposition, and covered with a conductive metal electrode layer. As of 2011 transfer-printing was capable to print onto target substrates up to 500mm X 400mm. this size limit needs to expand for transfer-printing to become a common process for the fabrication of large OLED/AMOLED displays.[61]


For a high resolution display like a TV, a TFT backplane is necessary to drive the pixels correctly. Currently, low temperature polycrystalline silicon (LTPS) – thin-film transistor (TFT) is used for commercial AMOLED displays. LTPS-TFT has variation of the performance in a display, so various compensation circuits have been reported.[59] Due to the size limitation of the excimer laser used for LTPS, the AMOLED size was limited. To cope with the hurdle related to the panel size, amorphous-silicon/microcrystalline-silicon backplanes have been reported with large display prototype demonstrations.[60]

Backplane technologies

[58] Like

Conventional OLED displays are formed by vapor thermal evaporation (VTE) and are patterned by shadow-mask. A mechanical mask has openings allowing the vapor to pass only on the desired location.

Organic vapour jet printing (OVJP) uses an inert carrier gas, such as micrometre-sized nozzle or nozzle array close to the substrate as it is being translated. This allows printing arbitrary multilayer patterns without the use of solvents.

Colour patterning can be accomplished by means of laser, such as radiation-induced sublimation transfer (RIST).[57]

Patternable organic light-emitting devices use a light or heat activated electroactive layer. A latent material (PEDOT-TMA) is included in this layer that, upon activation, becomes highly efficient as a hole injection layer. Using this process, light-emitting devices with arbitrary patterns can be prepared.[56]

Patterning technologies

Bottom or top emission
Bottom or top distinction refers not to orientation of the OLED display, but to the direction that emitted light exits the device. OLED devices are classified as bottom emission devices if light emitted passes through the transparent or semi-transparent bottom electrode and substrate on which the panel was manufactured. Top emission devices are classified based on whether or not the light emitted from the OLED device exits through the lid that is added following fabrication of the device. Top-emitting OLEDs are better suited for active-matrix applications as they can be more easily integrated with a non-transparent transistor backplane. The TFT array attached to the bottom substrate on which AMOLEDs are manufactured are typically non-transparent, resulting in considerable blockage of transmitted light if the device followed a bottom emitting scheme.[53]
Transparent OLEDs
Transparent OLEDs use transparent or semi-transparent contacts on both sides of the device to create displays that can be made to be both top and bottom emitting (transparent). TOLEDs can greatly improve contrast, making it much easier to view displays in bright sunlight.[54] This technology can be used in Head-up displays, smart windows or augmented reality applications.
Graded Heterojunction
Graded heterojunction OLEDs gradually decrease the ratio of electron holes to electron transporting chemicals.[25] This results in almost double the quantum efficiency of existing OLEDs.
Stacked OLEDs
Stacked OLEDs use a pixel architecture that stacks the red, green, and blue subpixels on top of one another instead of next to one another, leading to substantial increase in gamut and color depth, and greatly reducing pixel gap. Currently, other display technologies have the RGB (and RGBW) pixels mapped next to each other decreasing potential resolution.
Inverted OLED
In contrast to a conventional OLED, in which the anode is placed on the substrate, an Inverted OLED uses a bottom cathode that can be connected to the drain end of an n-channel TFT especially for the low cost amorphous silicon TFT backplane useful in the manufacturing of AMOLED displays.[55]


Device architectures

Applications of OLEDs in solid state lighting require the achievement of high brightness with good CIE coordinates (for white emission). The use of macromolecular species like polyhedral oligomeric silsesquioxanes (POSS) in conjunction with the use of phosphorescent species such as Ir for printed OLEDs have exhibited brightnesses as high as 10,000 cd/m2.[52]

The heavy metal atom at the centre of these complexes exhibits strong spin-orbit coupling, facilitating intersystem crossing between singlet and triplet states. By using these phosphorescent materials, both singlet and triplet excitons will be able to decay radiatively, hence improving the internal quantum efficiency of the device compared to a standard PLED where only the singlet states will contribute to emission of light.

Typically, a polymer such as poly(Iridium complexes[50] such as Ir(mppy)3[48] are currently the focus of research, although complexes based on other heavy metals such as platinum[49] have also been used.

Phosphorescent organic light emitting diodes use the principle of electrophosphorescence to convert electrical energy in an OLED into light in a highly efficient manner,[49][50] with the internal quantum efficiencies of such devices approaching 100%.[51]

Ir(mppy)3, a phosphorescent dopant which emits green light.[48]

Phosphorescent materials

While unsubstituted poly(p-phenylene vinylene) (PPV) is typically insoluble, a number of PPVs and related poly(naphthalene vinylene)s (PNVs) that are soluble in organic solvents or water have been prepared via ring opening metathesis polymerization.[44][45][46] These water soluble polymers or conjugated poly electrolytes (CPEs) also can be used as hole injection layers alone or in combination with nanoparticles like graphene.[47]

Typical polymers used in PLED displays include derivatives of poly(p-phenylene vinylene) and polyfluorene. Substitution of side chains onto the polymer backbone may determine the colour of emitted light[42] or the stability and solubility of the polymer for performance and ease of processing.[43]

Vacuum deposition is not a suitable method for forming thin films of polymers. However, polymers can be processed in solution, and spin coating is a common method of depositing thin polymer films. This method is more suited to forming large-area films than thermal evaporation. No vacuum is required, and the emissive materials can also be applied on the substrate by a technique derived from commercial inkjet printing.[40][41] However, as the application of subsequent layers tends to dissolve those already present, formation of multilayer structures is difficult with these methods. The metal cathode may still need to be deposited by thermal evaporation in vacuum. An alternative method to vacuum deposition is to deposit a Langmuir-Blodgett film.

Polymer light-emitting diodes (PLED), also light-emitting polymers (LEP), involve an electroluminescent conductive polymer that emits light when connected to an external voltage. They are used as a thin film for full-spectrum colour displays. Polymer OLEDs are quite efficient and require a relatively small amount of power for the amount of light produced.

poly(p-phenylene vinylene), used in the first PLED[21]

Polymer light-emitting diodes

Researchers report luminescence from a single polymer molecule, representing the smallest possible organic light-emitting diode (OLED) device.[38] Scientists will be able to optimize substances to produce more powerful light emissions. Finally, this work is a first step towards making molecule-sized components that combine electronic and optical properties. Similar components could form the basis of a molecular computer.[39]

Coherent emission from a laser dye-doped tandem SM-OLED device, excited in the pulsed regime, has been demonstrated.[36] The emission is nearly diffraction limited with a spectral width similar to that of broadband dye lasers.[37]

The production of small molecule devices and displays usually involves thermal evaporation in a vacuum. This makes the production process more expensive and of limited use for large-area devices, than other processing techniques. However, contrary to polymer-based devices, the vacuum deposition process enables the formation of well controlled, homogeneous films, and the construction of very complex multi-layer structures. This high flexibility in layer design, enabling distinct charge transport and charge blocking layers to be formed, is the main reason for the high efficiencies of the small molecule OLEDs.

Molecules commonly used in OLEDs include organometallic dendrimers. A number of materials are used for their charge transport properties, for example triphenylamine and derivatives are commonly used as materials for hole transport layers.[34] Fluorescent dyes can be chosen to obtain light emission at different wavelengths, and compounds such as perylene, rubrene and quinacridone derivatives are often used.[35] Alq3 has been used as a green emitter, electron transport material and as a host for yellow and red emitting dyes.

Efficient OLEDs using small molecules were first developed by Dr. Ching W. Tang et al.[20] at Eastman Kodak. The term OLED traditionally refers specifically to this type of device, though the term SM-OLED is also in use.[22]

Alq3,[20] commonly used in small molecule OLEDs

Small molecules

Material technologies

[33][32][31] Single carrier devices are typically used to study the

Experimental research has proven that the properties of the anode, specifically the anode/hole transport layer (HTL) interface topography plays a major role in the efficiency, performance, and lifetime of organic light emitting diodes. Imperfections in the surface of the anode decrease anode-organic film interface adhesion, increase electrical resistance, and allow for more frequent formation of non-emissive dark spots in the OLED material adversely affecting lifetime. Mechanisms to decrease anode roughness for ITO/glass substrates include the use of thin films and self-assembled monolayers. Also, alternative substrates and anode materials are being considered to increase OLED performance and lifetime. Possible examples include single crystal sapphire substrates treated with gold (Au) film anodes yielding lower work functions, operating voltages, electrical resistance values, and increasing lifetime of OLEDs.[30]

to avoid degradation. aluminium Such metals are reactive, so they require a capping layer of [29]

As electrons and holes are spin–orbit interactions to facilitate intersystem crossing between singlet and triplet states, thus obtaining emission from both singlet and triplet states and improving the internal efficiency.

During operation, a voltage is applied across the OLED such that the anode is positive with respect to the cathode. Anodes are picked based upon the quality of their optical transparency, electrical conductivity, and chemical stability.[27] A current of mobile than electrons. The decay of this excited state results in a relaxation of the energy levels of the electron, accompanied by emission of radiation whose frequency is in the visible region. The frequency of this radiation depends on the band gap of the material, in this case the difference in energy between the HOMO and LUMO.

Originally, the most basic polymer OLEDs consisted of a single organic layer. One example was the first light-emitting device synthesised by J. H. Burroughes et al., which involved a single layer of poly(p-phenylene vinylene). However multilayer OLEDs can be fabricated with two or more layers in order to improve device efficiency. As well as conductive properties, different materials may be chosen to aid charge injection at electrodes by providing a more gradual electronic profile,[23] or block a charge from reaching the opposite electrode and being wasted.[24] Many modern OLEDs incorporate a simple bilayer structure, consisting of a conductive layer and an emissive layer. More recent developments in OLED architecture improves quantum efficiency (up to 19%) by using a graded heterojunction.[25] In the graded heterojunction architecture, the composition of hole and electron-transport materials varies continuously within the emissive layer with a dopant emitter. The graded heterojunction architecture combines the benefits of both conventional architectures by improving charge injection while simultaneously balancing charge transport within the emissive region.[26]

[22] A typical OLED is composed of a layer of organic materials situated between two electrodes, the

Schematic of a bilayer OLED: 1. Cathode (−), 2. Emissive Layer, 3. Emission of radiation, 4. Conductive Layer, 5. Anode (+)

Working principle

Universal Display Corporation holds the majority of patents concerning the commercialization of OLEDs.

Research into polymer electroluminescence culminated in 1990 with J. H. Burroughes et al. at the Cavendish Laboratory in Cambridge reporting a high efficiency green light-emitting polymer based device using 100 nm thick films of poly(p-phenylene vinylene).[21]

Ching W. Tang and Steven Van Slyke at Eastman Kodak reported the first diode device in 1987.[20] This device used a novel two-layer structure with separate hole transporting and electron transporting layers such that recombination and light emission occurred in the middle of the organic layer; this resulted in a reduction in operating voltage and improvements in efficiency that led to the current era of OLED research and device production.

Roger Partridge made the first observation of electroluminescence from polymer films at the National Physical Laboratory in the United Kingdom. The device consisted of a film of poly(N-vinylcarbazole) up to 2.2 micrometres thick located between two charge injecting electrodes. The results of the project were patented in 1975[15] and published in 1983.[16][17][18][19]

Pope's group reported in 1965[12] that in the absence of an external electric field, the electroluminescence in anthracene crystals is caused by the recombination of a thermalized electron and hole, and that the conducting level of anthracene is higher in energy than the exciton energy level. Also in 1965, W. Helfrich and W. G. Schneider of the National Research Council in Canada produced double injection recombination electroluminescence for the first time in an anthracene single crystal using hole and electron injecting electrodes,[13] the forerunner of modern double-injection devices. In the same year, Dow Chemical researchers patented a method of preparing electroluminescent cells using high-voltage (500–1500 V) AC-driven (100–3000 Hz) electrically insulated one millimetre thin layers of a melted phosphor consisting of ground anthracene powder, tetracene, and graphite powder.[14] Their proposed mechanism involved electronic excitation at the contacts between the graphite particles and the anthracene molecules.

. The proposed mechanism was field-accelerated electron excitation of molecular fluorescence. volts using a small area silver electrode at 400 [11] in 1963tetracene and on anthracene crystals doped with anthracene) for hole and electron injecting electrode contacts. These contacts are the basis of charge injection in all modern OLED devices. Pope's group also first observed direct current (DC) electroluminescence under vacuum on a single pure crystal of work functions They further described the necessary energetic requirements ([10][9][8]

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