Metal–Organic and Organic TADF-Materials: Status, Challenges and Characterization

  • Larissa Bergmann
  • Daniel M. Zink
  • Stefan BräseEmail author
  • Thomas BaumannEmail author
  • Daniel VolzEmail author
Part of the following topical collections:
  1. Photoluminescent Materials and Electroluminescent Devices


This section covers both metal–organic and organic materials that feature thermally activated delayed fluorescence (TADF). Such materials are especially useful for organic light-emitting diodes (OLEDs), a technology that was introduced in commercial displays only recently. We compare both material classes to show commonalities and differences, highlighting current issues and challenges. Advanced spectroscopic techniques as valuable tools to develop solutions to those issues are introduced. Finally, we provide an outlook over the field and highlight future trends.


OLED Copper(I) Organic Singlet harvesting Thermally activated delayed fluorescence 



The authors thank the German Ministry for Education and Research (BMBF) for funding in the scope of the cyCESH project (FKN 13N12668). Funding through the Deutsche Forschungsgemeinschaft (TRR88, B2; SFB 1176) is acknowledged. We gratefully acknowledge the collaboration with the groups of Prof. Ifor Samuel (University of St. Andrews), Prof. Franky So (NCSU), Prof. Christopher Barner-Kowollik (KIT), Prof. Clemens Heske (KIT, UNLV), Prof. Uli Lemmer (KIT), and Manuela Wallesch (KIT) as well as the scientific division of CYNORA and the synchrotron facilities of KIT, Angstromquelle Karlsruhe (ANKA).


  1. 1.
    Volz D, Wallesch M, Fléchon C, Danz M, Verma A, Navarro JM, Zink DM, Bräse S, Baumann T (2015) From iridium and platinum to copper and carbon: new avenues for more sustainability in organic light-emitting diodes. Green Chem 17:1988–2011. doi: 10.1039/C4GC02195A CrossRefGoogle Scholar
  2. 2.
    Jankus V, Data P, Graves D, McGuinness C, Santos J, Bryce MR, Dias FB, Monkman AP (2014) Highly efficient TADF OLEDs: how the emitter-host interaction controls both the excited state species and electrical properties of the devices to achieve near 100% triplet harvesting and high efficiency. Adv Funct Mater. doi: 10.1002/adfm.201400948 Google Scholar
  3. 3.
    Zhang Q, Tsang D, Kuwabara H, Hatae Y, Li B, Takahashi T, Lee SY, Yasuda T, Adachi C (2015) Nearly 100% internal quantum efficiency in undoped electroluminescent devices employing pure organic emitters. Adv Mater 27:2096–2100. doi: 10.1002/adma.201405474 CrossRefGoogle Scholar
  4. 4.
    Zhang Q, Li B, Huang S, Nomura H, Tanaka H, Adachi C (2014) Efficient blue organic light-emitting diodes employing thermally activated delayed fluorescence. Nat Photonics 8:326–332. doi: 10.1038/nphoton.2014.12 CrossRefGoogle Scholar
  5. 5.
    Goushi K, Yoshida K, Sato K, Adachi C (2012) Organic light-emitting diodes employing efficient reverse intersystem crossing for triplet-to-singlet state conversion. Nat Photonics 6:253–258. doi: 10.1038/nphoton.2012.31 CrossRefGoogle Scholar
  6. 6.
    Uoyama H, Goushi K, Shizu K, Nomura H, Adachi C (2012) Highly efficient organic light-emitting diodes from delayed fluorescence. Nature 492:234–238. doi: 10.1038/nature11687 CrossRefGoogle Scholar
  7. 7.
    Volz D, Cheng Y, Liu R, Wallesch M, Zink D, Göttlicher J, Steininger R, Flügge H, Fléchon C, Navarro J, Bräse S, So F, Baumann T (2015) High-efficiency OLEDs with fully-bridged PyrPHOS-complexes using Singlet Harvesting. Adv Mater. doi: 10.1002/adma.201405897 Google Scholar
  8. 8.
    Deaton JC, Switalski SC, Kondakov DY, Young RH, Pawlik TD, Giesen DJ, Harkins SB, Miller AJM, Mickenberg SF, Peters JC (2010) E-type delayed fluorescence of a phosphine-supported Cu2(mu-NAr2)2 diamond core: harvesting singlet and triplet excitons in OLEDs. J Am Chem Soc 132:9499–9508. doi: 10.1021/ja1004575 CrossRefGoogle Scholar
  9. 9.
    Parker CA, Hatchard CG (1961) Triplet-singlet emission in fluid solutions. Phosphorescence of eosin. Trans Faraday Soc 57:1894. doi: 10.1039/tf9615701894 CrossRefGoogle Scholar
  10. 10.
    Berberan-Santos MN, Garcia JMM (1996) Unusually strong delayed fluorescence of C70. J Am Chem Soc 118:9391–9394. doi: 10.1021/ja961782s CrossRefGoogle Scholar
  11. 11.
    Kirchhoff JR, Gamache RE, Blaskie MW, Del Paggio AA, Lengel RK, McMillin DR (1983) Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states. Inorg Chem 22:2380–2384. doi: 10.1021/ic00159a008 CrossRefGoogle Scholar
  12. 12.
    Endo A, Ogasawara M, Takahashi A, Yokoyama D, Kato Y, Adachi C (2009) Thermally activated delayed fluorescence from Sn(4+)-porphyrin complexes and their application to organic light emitting diodes–a novel mechanism for electroluminescence. Adv Mater 21:4802–4806. doi: 10.1002/adma.200900983 CrossRefGoogle Scholar
  13. 13.
    Blaskie MW, McMillin DR (1980) Photostudies of copper(I) systems. 6. Room-temperature emission and quenching studies of bis(2,9-dimethyl-1,10-phenanthroline)copper(I). Inorg Chem 19:3519–3522. doi: 10.1021/ic50213a062 CrossRefGoogle Scholar
  14. 14.
    Baleizão C, Berberan-Santos MN (2008) Thermally activated delayed fluorescence in fullerenes. Ann NY Acad Sci 1130:224–234. doi: 10.1196/annals.1430.044 CrossRefGoogle Scholar
  15. 15.
    Lee DR, Kim BS, Lee CW, Im Y, Yook KS, Hwang S-H, Lee JY (2015) Above 30% external quantum efficiency in green delayed fluorescent organic light-emitting diodes. ACS Appl Mater Interfaces 7:9625–9629. doi: 10.1021/acsami.5b01220 CrossRefGoogle Scholar
  16. 16.
    Volz D, Chen Y, Wallesch M, Liu R, Fléchon C, Zink DM, Friedrichs J, Flügge H, Steininger R, Göttlicher J, Heske C, Weinhardt L, Bräse S, So F, Baumann T (2015) Bridging the efficiency gap: fully bridged dinuclear Cu(I)-complexes for singlet harvesting in high-efficiency OLEDs. Adv Mater 27:2538–2543. doi: 10.1002/adma.201405897 CrossRefGoogle Scholar
  17. 17.
    Volz D, Zink DM, Bocksrocker T, Friedrichs J, Nieger M, Baumann T, Lemmer U, Bräse S (2013) Molecular construction kit for tuning solubility, stability and luminescence properties: heteroleptic MePyrPHOS-copper iodide-complexes and their application in organic light-emitting diodes. Chem Mater 25:3414–3426. doi: 10.1021/cm4010807 CrossRefGoogle Scholar
  18. 18.
    Flügge H, Rohr A, Döring S, Fléchon C, Wallesch M, Zink D, Seeser J, Leganés J, Sauer T, Rabe T, Kowalsky W, Baumann T, Volz D (2015) Reduced concentration quenching in a TADF-type copper(I)-emitter. In: So F, Adachi C, Kim J-J (eds) Proceedings of SPIE. p 95661PGoogle Scholar
  19. 19.
    Goushi K, Adachi C (2012) Efficient organic light-emitting diodes through up-conversion from triplet to singlet excited states of exciplexes. Appl Phys Lett 101:023306. doi: 10.1063/1.4737006 CrossRefGoogle Scholar
  20. 20.
    Yersin H, Rausch AF, Czerwieniec R, Hofbeck T, Fischer T (2011) The triplet state of organo-transition metal compounds. Triplet harvesting and singlet harvesting for efficient OLEDs. Coord Chem Rev 255:2622–2652. doi: 10.1016/j.ccr.2011.01.042 CrossRefGoogle Scholar
  21. 21.
    Montalti M, Credi A, Prodi L, Gandolfi MT (2006) Handbook of Photochemistry. CRC Press, Boca RatonGoogle Scholar
  22. 22.
    Salazar FA, Fedorov A, Berberan-Santos MN (1997) A study of thermally activated delayed fluorescence in C60. Chem Phys Lett 271:361–366. doi: 10.1016/S0009-2614(97)00469-7 CrossRefGoogle Scholar
  23. 23.
    Adachi C (2014) Third-generation organic electroluminescence materials. Jpn J Appl Phys. doi: 10.7567/JJAP.53.060101 Google Scholar
  24. 24.
    Li EY, Jiang T, Chi Y, Chou P-T, Yu-Tzu Li E, Jiang T, Chi Y, Chou P-T (2014) Semi-quantitative assessment of the intersystem crossing rate: an extension of the El-Sayed rule to the emissive transition metal complexes. Phys Chem Chem Phys 16:26184–26192. doi: 10.1039/C4CP03540B CrossRefGoogle Scholar
  25. 25.
    Kretzschmar A, Patze C, Schwaebel ST, Bunz UHF (2015) Development of thermally activated delayed fluorescence materials with shortened emissive lifetimes. J Org Chem 80:9126–9131. doi: 10.1021/acs.joc.5b01496 CrossRefGoogle Scholar
  26. 26.
    Czerwieniec R, Yu J, Yersin H (2011) Blue-light emission of Cu(I) complexes and singlet harvesting. Inorg Chem 50:8293–8301. doi: 10.1021/ic200811a CrossRefGoogle Scholar
  27. 27.
    Lee J, Shizu K, Tanaka H, Nakanotani H, Yasuda T, Kaji H, Adachi C (2015) Controlled emission colors and singlet–triplet energy gaps of dihydrophenazine-based thermally activated delayed fluorescence emitters. J Mater Chem C 3:2175–2181. doi: 10.1039/C4TC02530J CrossRefGoogle Scholar
  28. 28.
    Sato K, Shizu K, Yoshimura K, Kawada A, Miyazaki H, Adachi C (2013) Organic luminescent molecule with energetically equivalent singlet and triplet excited states for organic light-emitting diodes. Phys Rev Lett 110:247401. doi: 10.1103/PhysRevLett.110.247401 CrossRefGoogle Scholar
  29. 29.
    Leitl MJ, Krylova VA, Djurovich PI, Thompson ME, Yersin H (2014) Phosphorescence versus thermally activated delayed fluorescence. Controlling singlet-triplet splitting in brightly emitting and sublimable Cu(I) compounds. J Am Chem Soc 136:16032–16038. doi: 10.1021/ja508155x CrossRefGoogle Scholar
  30. 30.
    Czerwieniec R, Kowalski K, Yersin H (2013) Highly efficient thermally activated fluorescence of a new rigid Cu(I) complex [Cu(dmp)(phanephos)]+. Dalt Trans 42:9826–9830. doi: 10.1039/c3dt51006a CrossRefGoogle Scholar
  31. 31.
    Yersin H, Czerwieniec R (2012) Organometallic emitters for OLEDs. Triplet harvesting, singlet harvesting, case studies, and trends. In: Brütting W, Adachi C (eds) Physics of organic semiconductor, 2nd edn. Wiley, Weinheim, p 371Google Scholar
  32. 32.
    Yersin H, Czerwieniec R, Hupfer A (2012) Singlet harvesting with brightly emitting Cu(I) and metal-free organic compounds. In: Rand BP, Adachi C, van Elsbergen V (eds) Proceedings of SPIE. pp 843508–843508–10Google Scholar
  33. 33.
    Osawa M (2014) Highly efficient blue-green delayed fluorescence from copper(I) thiolate complexes: luminescence color alteration by orientation change of the aryl ring. Chem Commun 50:1801–1803. doi: 10.1039/c3cc47871h CrossRefGoogle Scholar
  34. 34.
    Osawa M, Hoshino M, Hashimoto M, Kawata I, Igawa S, Yashima M (2014) Application of three-coordinate copper(i) complexes with halide ligands in organic light-emitting diodes that exhibit delayed fluorescence. Dalton Trans. doi: 10.1039/c4dt02853h Google Scholar
  35. 35.
    Osawa M, Kawata I, Ishii R, Igawa S, Hashimoto M, Hoshino M (2013) Application of neutral d10 coinage metal complexes with an anionic bidentate ligand in delayed fluorescence-type organic light-emitting diodes. J Mater Chem C 1:4375. doi: 10.1039/c3tc30524d CrossRefGoogle Scholar
  36. 36.
    Hashimoto M, Igawa S, Yashima M, Kawata I, Hoshino M, Osawa M (2011) Highly efficient green organic light-emitting diodes containing luminescent three-coordinate copper(I) complexes. J Am Chem Soc 133:10348–10351. doi: 10.1021/ja202965y CrossRefGoogle Scholar
  37. 37.
    Turro NJ (1991) Modern molecular photochemistry. University Science Books, SausalitoGoogle Scholar
  38. 38.
    Zink DM, Bergmann L, Ambrosek D, Wallesch M, Volz D, Mydlak M (2014) Singlet harvesting copper-based emitters: a modular approach towards next-generation OLED technology. Transl Mater Res 1:015003. doi: 10.1088/2053-1613/1/1/015003 CrossRefGoogle Scholar
  39. 39.
    Sandanayaka ASD, Matsushima T, Adachi C (2015) Degradation mechanisms of organic light-emitting diodes based on thermally activated delayed fluorescence molecules. J Phys Chem C 119:23845–23851. doi: 10.1021/acs.jpcc.5b07084 CrossRefGoogle Scholar
  40. 40.
    Volz D, Bergmann L, Zink DM, Baumann T, Bräse S (2013) Are copper(I) complexes tough enough to be processed from solution? SPIE Newsroom. doi: 10.1117/2.1201308.005080 Google Scholar
  41. 41.
    Gaj MP, Fuentes-Hernandez C, Zhang Y, Marder SR, Kippelen B (2015) Highly efficient organic light-emitting diodes from thermally activated delayed fluorescence using a sulfone–carbazole host material. Org Electron 16:109–112. doi: 10.1016/j.orgel.2014.10.049 CrossRefGoogle Scholar
  42. 42.
    Komatsu R, Sasabe H, Inomata S, Pu Y-J, Kido J (2015) High efficiency solution processed OLEDs using a thermally activated delayed fluorescence emitter. Synth Met 202:165–168. doi: 10.1016/j.synthmet.2015.02.009 CrossRefGoogle Scholar
  43. 43.
    Suzuki Y, Zhang Q, Adachi C (2015) A solution-processable host material of 1,3-bis{3-[3-(9-carbazolyl)phenyl]-9-carbazolyl}benzene and its application in organic light-emitting diodes employing thermally activated delayed fluorescence. J Mater Chem C 3:1700–1706. doi: 10.1039/C4TC02211D CrossRefGoogle Scholar
  44. 44.
    Cho YJ, Yook KS, Lee JY (2014) High efficiency in a solution-processed thermally activated delayed-fluorescence device using a delayed-fluorescence emitting material with improved solubility. Adv Mater 26:6642–6646. doi: 10.1002/adma.201402188 CrossRefGoogle Scholar
  45. 45.
    Tang C, Yang T, Cao X, Tao Y, Wang F, Zhong C, Qian Y, Zhang X, Huang W (2015) Tuning a weak emissive blue host to highly efficient green dopant by a CN in tetracarbazolepyridines for solution-processed thermally activated delayed fluorescence devices. Adv Opt Mater. doi: 10.1002/adom.201500016 Google Scholar
  46. 46.
    Drozdov A, Troyanov SI, Pettinari C, Marchetti F, Santini C, Pettinari R, Battiston GA, Gerbasi R (2001) New volatile polyazolylborates of copper(I) for MOCVD. Le J Phys. doi: 10.1051/jp4:2001374 Google Scholar
  47. 47.
    Pettinari C, Marchetti F, Santini C, Pettinari R, Drozdov A, Troyanov S, Battiston GA, Gerbasi R, Pettinari C, Drozdov A (2001) Structure and volatility of copper complexes containing pyrazolyl-based ligands. Inorg Chim Acta 315:88–95. doi: 10.1016/S0020-1693(01)00330-9 CrossRefGoogle Scholar
  48. 48.
    Varathan E, Vijay D, Subramanian V (2014) Rational design of carbazole- and carboline-based ambipolar host materials for blue electrophosphorescence: a density functional theory study. J Phys Chem C 118:21741–21754. doi: 10.1021/jp500665k CrossRefGoogle Scholar
  49. 49.
    Liu F, Paul Ruden P, Campbell IH, Smith DL (2011) Exciplex current mechanism for ambipolar bilayer organic light emitting diodes. Appl Phys Lett 99:123301. doi: 10.1063/1.3640232 CrossRefGoogle Scholar
  50. 50.
    Yook KS, Lee JY (2014) Small molecule host materials for solution processed phosphorescent organic light-emitting diodes. Adv Mater 26:1–16. doi: 10.1002/adma.201306266 CrossRefGoogle Scholar
  51. 51.
    Tao Y, Yang C, Qin J (2011) Organic host materials for phosphorescent organic light-emitting diodes. Chem Soc Rev 40:2943–2970. doi: 10.1039/c0cs00160k CrossRefGoogle Scholar
  52. 52.
    Xiao L, Chen Z, Qu B, Luo J, Kong S, Gong Q, Kido J (2011) Recent progresses on materials for electrophosphorescent organic light-emitting devices. Adv Mater 23:926–952. doi: 10.1002/adma.201003128 CrossRefGoogle Scholar
  53. 53.
    Li J, Nakagawa T, MacDonald J, Zhang Q, Nomura H, Miyazaki H, Adachi C (2013) Highly efficient organic light-emitting diode based on a hidden thermally activated delayed fluorescence channel in a heptazine derivative. Adv Mater 25:3319–3323. doi: 10.1002/adma.201300575 CrossRefGoogle Scholar
  54. 54.
    Wang S, Yan X, Cheng Z, Zhang H, Liu Y, Wang Y (2015) Highly efficient near-infrared delayed fluorescence organic light emitting diodes using a phenanthrene-based charge-transfer compound. Angew Chem Int Ed 54:13068–13072. doi: 10.1002/anie.201506687 CrossRefGoogle Scholar
  55. 55.
    Méhes G, Nomura H, Zhang Q, Nakagawa T, Adachi C (2012) Enhanced electroluminescence efficiency in a spiro-acridine derivative through thermally activated delayed fluorescence. Angew Chem Int Ed Engl 51:11311–11315. doi: 10.1002/anie.201206289 CrossRefGoogle Scholar
  56. 56.
    Tanaka H, Shizu K, Nakanotani H, Adachi C (2014) Dual intramolecular charge-transfer fluorescence derived from a phenothiazine-triphenyltriazine derivative. J Phys Chem C 118:15985–15994. doi: 10.1021/jp501017f CrossRefGoogle Scholar
  57. 57.
    Tanaka H, Shizu K, Miyazaki H, Adachi C (2012) Efficient green thermally activated delayed fluorescence (TADF) from a phenoxazine–triphenyltriazine (PXZ–TRZ) derivative. Chem Commun 48:11392. doi: 10.1039/c2cc36237f CrossRefGoogle Scholar
  58. 58.
    Endo A, Sato K, Yoshimura K, Kai T, Kawada A, Miyazaki H, Adachi C (2011) Efficient up-conversion of triplet excitons into a singlet state and its application for organic light emitting diodes. Appl Phys Lett 98:083302. doi: 10.1063/1.3558906 CrossRefGoogle Scholar
  59. 59.
    Cho YJ, Jeon SK, Chin BD, Yu E, Lee JY (2015) The design of dual emitting cores for green thermally activated delayed fluorescent materials. Angew Chem Int Ed. doi: 10.1002/anie.201412107 Google Scholar
  60. 60.
    Kim M, Jeon SK, Hwang S, Lee JY (2015) Stable blue thermally activated delayed fluorescent organic light-emitting diodes with three times longer lifetime than phosphorescent organic light-emitting diodes. Adv Mater 27:1–6. doi: 10.1002/adma.201500267 CrossRefGoogle Scholar
  61. 61.
    Tanaka H, Shizu K, Nakanotani H, Adachi C (2013) Twisted intramolecular charge transfer state for long-wavelength thermally activated delayed fluorescence. Chem Mater 25:3766–3771. doi: 10.1021/cm402428a CrossRefGoogle Scholar
  62. 62.
    Zhang Q, Kuwabara H, Potscavage WJ, Huang S, Hatae Y, Shibata T, Adachi C (2014) Anthraquinone-based intramolecular-charge-transfer compounds: computational molecular design, thermally activated delayed fluorescence, and highly-efficient red electroluminescence. J Am Chem Soc 136:18070–18081. doi: 10.1021/ja510144h CrossRefGoogle Scholar
  63. 63.
    Sun JW, Lee J-H, Moon C-K, Kim K-H, Shin H, Kim J-J (2014) A fluorescent organic light-emitting diode with 30 % external quantum efficiency. Adv Mater 26:5684–5688. doi: 10.1002/adma.201401407 CrossRefGoogle Scholar
  64. 64.
    Nakanotani H, Masui K, Nishide J, Shibata T, Adachi C (2013) Promising operational stability of high-efficiency organic light-emitting diodes based on thermally activated delayed fluorescence. Sci Rep 3:2127. doi: 10.1038/srep02127 CrossRefGoogle Scholar
  65. 65.
    Liu W, Zheng C-J, Wang K, Chen Z, Chen D-Y, Li F, Ou X-M, Dong Y-P, Zhang X-H (2015) Novel carbazol-pyridine-carbonitrile derivative as excellent blue thermally activated delayed fluorescence emitter for highly efficient organic light-emitting devices. ACS Appl Mater Interfaces. doi: 10.1021/acsami.5b05648 Google Scholar
  66. 66.
    Youn Lee S, Yasuda T, Nomura H, Adachi C (2012) High-efficiency organic light-emitting diodes utilizing thermally activated delayed fluorescence from triazine-based donor–acceptor hybrid molecules. Appl Phys Lett. doi: 10.1063/1.4749285 Google Scholar
  67. 67.
    Serevičius T, Nakagawa T, Kuo M-C, Cheng S-H, Wong K-T, Chang C-H, Kwong RC, Xia S, Adachi C (2013) Enhanced electroluminescence based on thermally activated delayed fluorescence from a carbazole-triazine derivative. Phys Chem Chem Phys 15:15850–15855. doi: 10.1039/c3cp52255e CrossRefGoogle Scholar
  68. 68.
    Hu J, Li Y, Zhu H, Qiu S, He G, Zhu X, Xia A (2015) Photophysical properties of intramolecular charge transfer in a tribranched donor-π-acceptor chromophore. ChemPhysChem 16:2357–2365. doi: 10.1002/cphc.201500290 CrossRefGoogle Scholar
  69. 69.
    Kim SM, Byeon SY, Hwang S-H, Lee JY (2015) Rational design of host materials for phosphorescent organic light-emitting diodes by modifying the 1-position of carbazole. Chem Commun 51:10672–10675. doi: 10.1039/C5CC02188J CrossRefGoogle Scholar
  70. 70.
    Tsai W-L, Huang M-H, Lee W-K, Hsu Y-J, Pan K-C, Huang Y-H, Ting H-C, Sarma M, Ho Y-Y, Hu H-C, Chen C-C, Lee M-T, Wong K-T, Wu C-C (2015) A versatile thermally activated delayed fluorescence emitter for both highly efficient doped and non-doped organic light emitting devices. Chem Commun. doi: 10.1039/C5CC05022G Google Scholar
  71. 71.
    Chen W-C, Lee C-S, Tong Q-X (2015) Blue-emitting organic electrofluorescence materials: progress and prospective. J Mater Chem C. doi: 10.1039/C5TC02420J Google Scholar
  72. 72.
    Tao Y, Yuan K, Chen T, Xu P, Li H, Chen R, Zheng C, Zhang L, Huang W (2014) Thermally activated delayed fluorescence materials towards the breakthrough of organoelectronics. Adv Mater 26:7931–7958. doi: 10.1002/adma.201402532 CrossRefGoogle Scholar
  73. 73.
    Lee DR, Kim M, Jeon SK, Hwang S-H, Lee CW, Lee JY (2015) Design strategy for 25% external quantum efficiency in green and blue thermally activated delayed fluorescent devices. Adv Mater 27:5861–5867. doi: 10.1002/adma.201502053 CrossRefGoogle Scholar
  74. 74.
    Higuchi T, Nakanotani H, Adachi C (2015) High-efficiency white organic light-emitting diodes based on a blue thermally activated delayed fluorescent emitter combined with green and red fluorescent emitters. Adv Mater. doi: 10.1002/adma.201404967 Google Scholar
  75. 75.
    Dias FB, Bourdakos KN, Jankus V, Moss KC, Kamtekar KT, Bhalla V, Santos J, Bryce MR, Monkman AP (2013) Triplet harvesting with 100% efficiency by way of thermally activated delayed fluorescence in charge transfer OLED emitters. Adv Mater 25:3707–3714. doi: 10.1002/adma.201300753 CrossRefGoogle Scholar
  76. 76.
    Wang H, Xie L, Peng Q, Meng L, Wang Y, Yi Y, Wang P (2014) Novel thermally activated delayed fluorescence materials-thioxanthone derivatives and their applications for highly efficient OLEDs. Adv Mater. doi: 10.1002/adma.201401393 Google Scholar
  77. 77.
    Huang B, Qi Q, Jiang W, Tang J, Liu Y, Fan W, Yin Z, Shi F, Ban X, Xu H, Sun Y (2014) Thermally activated delayed fluorescence materials based on 3,6-di-tert-butyl-9-((phenylsulfonyl)phenyl)-9H-carbazoles. Dye Pigment 111:135–144. doi: 10.1016/j.dyepig.2014.06.008 CrossRefGoogle Scholar
  78. 78.
    Lin N, Qiao J, Duan L, Wang L, Qiu Y (2014) Molecular understanding of the chemical stability of organic materials for OLEDs: a comparative study on sulfonyl, phosphine-oxide, and carbonyl-containing host materials. J Phys Chem C 118:7569–7578. doi: 10.1021/jp412614k CrossRefGoogle Scholar
  79. 79.
    Lee SY, Yasuda T, Yang YS, Zhang Q, Adachi C (2014) Luminous butterflies: efficient exciton harvesting by benzophenone derivatives for full-color delayed fluorescence OLEDs. Angew Chem Int Ed Engl 53:6402–6406. doi: 10.1002/anie.201402992 CrossRefGoogle Scholar
  80. 80.
    Numata M, Yasuda T, Adachi C (2015) High efficiency pure blue thermally activated delayed fluorescence molecules having 10H-phenoxaborin and acridan units. Chem Commun 51:9443–9446. doi: 10.1039/C5CC00307E CrossRefGoogle Scholar
  81. 81.
    Reineke S (2014) Organic light-emitting diodes: phosphorescence meets its match. Nat Photonics 8:269–270. doi: 10.1038/nphoton.2014.78 CrossRefGoogle Scholar
  82. 82.
    Penfold TJ (2015) On predicting the excited state properties of thermally activated delayed fluorescence emitters. J Phys Chem C. doi: 10.1021/acs.jpcc.5b03530 Google Scholar
  83. 83.
    Huang S, Zhang Q, Shiota Y, Nakagawa T, Kuwabara K, Yoshizawa K, Adachi C (2013) Computational prediction for singlet- and triplet-transition energies of charge-transfer compounds. J Chem Theory Comput 9:3872–3877. doi: 10.1021/ct400415r CrossRefGoogle Scholar
  84. 84.
    Liu X-K, Chen Z, Zheng C, Liu C, Lee C, Li F, Ou X-M, Zhang X-H (2015) Prediction and design of efficient exciplex emitters for high-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes. Adv Mater 27:2378–2383. doi: 10.1002/adma.201405062 CrossRefGoogle Scholar
  85. 85.
    Czerwieniec R, Yersin H (2015) Diversity of copper(I) complexes showing thermally activated delayed fluorescence: basic photophysical analysis. Inorg Chem 54:4322–4327. doi: 10.1021/ic503072u CrossRefGoogle Scholar
  86. 86.
    Ralle M, Lutsenko S, Blackburn NJ, Strange RW, Reedijk J, Volbeda A, Farooq A, Karlin KD, Zubieta J (2003) X-ray absorption spectroscopy of the copper chaperone HAH1 reveals a linear two-coordinate Cu(I) center capable of adduct formation with exogenous thiols and phosphines. J Biol Chem 278:23163–23170. doi: 10.1074/jbc.M303474200 CrossRefGoogle Scholar
  87. 87.
    Wallesch M, Volz D, Zink DM, Schepers U, Nieger M, Baumann T, Bräse S (2014) Bright coppertunities: multinuclear Cu I complexes with N-P ligands and their applications. Chem A Eur J 20:6578–6590. doi: 10.1002/chem.201402060 CrossRefGoogle Scholar
  88. 88.
    Zink DM, Bächle M, Baumann T, Nieger M, Kühn M, Wang C, Klopper W, Monkowius U, Hofbeck T, Yersin H, Bräse S (2013) Synthesis, structure, and characterization of dinuclear copper(I) halide complexes with P^N ligands featuring exciting photoluminescence properties. Inorg Chem 52:2292–2305. doi: 10.1021/ic300979c CrossRefGoogle Scholar
  89. 89.
    Chen X-L, Yu R, Zhang Q-K, Zhou L-J, Wu X-Y, Zhang Q, Lu C-Z (2013) Rational design of strongly blue-emitting cuprous complexes with thermally activated delayed fluorescence and application in solution-processed OLEDs. Chem Mater 25:3910–3920. doi: 10.1021/cm4024309 CrossRefGoogle Scholar
  90. 90.
    Bergmann L, Friedrichs J, Mydlak M, Baumann T, Nieger M, Bräse S (2013) Outstanding luminescence from neutral copper(I) complexes with pyridyl-tetrazolate and phosphine ligands. Chem Commun (Camb) 49:6501–6503. doi: 10.1039/c3cc42280a CrossRefGoogle Scholar
  91. 91.
    Zink DM, Volz D, Baumann T, Mydlak M, Flügge H, Friedrichs J, Nieger M, Bräse S (2013) Heteroleptic, dinuclear copper(I) complexes for application in organic light-emitting diodes. Chem Mater 25:4471–4486. doi: 10.1021/cm4018375 CrossRefGoogle Scholar
  92. 92.
    Igawa S, Hashimoto M, Kawata I, Yashima M, Hoshino M, Osawa M, Ishii R (2013) Highly efficient green organic light-emitting diodes containing luminescent tetrahedral copper(i) complexes. J Mater Chem C 1:542. doi: 10.1039/c2tc00263a CrossRefGoogle Scholar
  93. 93.
    Volz D, Nieger M, Friedrichs J, Baumann T, Bräse S (2013) How the quantum efficiency of a highly emissive binuclear copper complex is enhanced by changing the processing solvent. Langmuir 29:3034–3044. doi: 10.1021/la3039522 CrossRefGoogle Scholar
  94. 94.
    Linfoot CL, Leitl MJ, Richardson P, Rausch AF, Chepelin O, White FJ, Yersin H, Robertson N (2014) Thermally activated delayed fluorescence (TADF) and enhancing photoluminescence quantum yields of [Cu(I)(diimine)(diphosphine)](+) complexes-photophysical, structural, and computational studies. Inorg Chem 53:10854–10861. doi: 10.1021/ic500889s CrossRefGoogle Scholar
  95. 95.
    Hofbeck T, Monkowius U, Yersin H (2015) Highly efficient luminescence of Cu(I) compounds: thermally activated delayed fluorescence combined with short-lived phosphorescence. J Am Chem Soc 137:399–404. doi: 10.1021/ja5109672 CrossRefGoogle Scholar
  96. 96.
    Kato M, Ohara H, Kobayashi A (2014) Simple and extremely efficient blue emitters based on mononuclear Cu(I)-halide complexes with delayed fluorescence. Dalt Trans. doi: 10.1039/C4DT02709D Google Scholar
  97. 97.
    Ohara H, Kobayashi A, Kato M (2014) Simple and extremely efficient blue emitters based on mononuclear Cu(I)-halide complexes with delayed fluorescence. Dalt Trans 43:17317–17323. doi: 10.1039/C4DT02709D CrossRefGoogle Scholar
  98. 98.
    Kaeser A, Mohankumar M, Mohanraj J, Monti F, Holler M, Cid J-J, Moudam O, Nierengarten I, Karmazin-Brelot L, Duhayon C, Delavaux-Nicot B, Armaroli N, Nierengarten J-F (2013) Heteroleptic copper(I) complexes prepared from phenanthroline and bis-phosphine ligands. Inorg Chem 52:12140–12151. doi: 10.1021/ic4020042 CrossRefGoogle Scholar
  99. 99.
    Tsuboyama A, Kuge K, Furugori M, Okada S, Hoshino M, Ueno K (2007) Photophysical properties of highly luminescent copper(I) halide complexes chelated with 1,2-bis(diphenylphosphino)benzene. Inorg Chem 46:1992–2001. doi: 10.1021/ic0608086 CrossRefGoogle Scholar
  100. 100.
    Leitl MJ, Küchle F-RR, Mayer HA, Wesemann L, Yersin H (2013) Brightly blue and green emitting Cu(I) dimers for singlet harvesting in OLEDs. J Phys Chem A 117:11823–11836. doi: 10.1021/jp402975d CrossRefGoogle Scholar
  101. 101.
    Finkenzeller W, Yersin H (2003) Emission of Ir(ppy)3. Temperature dependence, decay dynamics, and magnetic field properties. Chem Phys Lett 377:299–305. doi: 10.1016/S0009-2614(03)01142-4 CrossRefGoogle Scholar
  102. 102.
    Hager GD, Crosby GA (1975) Charge-transfer exited states of ruthenium(II) complexes. I. Quantum yield and decay measurements. J Am Chem Soc 97:7031–7037. doi: 10.1021/ja00857a013 CrossRefGoogle Scholar
  103. 103.
    Siddique ZA, Yamamoto Y, Ohno T, Nozaki K (2003) Structure-dependent photophysical properties of singlet and triplet metal-to-ligand charge transfer states in copper(I) bis(diimine) compounds. Inorg Chem 42:6366–6378. doi: 10.1021/ic034412v CrossRefGoogle Scholar
  104. 104.
    Iwamura M, Watanabe H, Ishii K, Takeuchi S, Tahara T (2011) Coherent nuclear dynamics in ultrafast photoinduced structural change of bis(diimine)copper(I) complex. J Am Chem Soc 133:7728–7736. doi: 10.1021/ja108645x CrossRefGoogle Scholar
  105. 105.
    Healy PC, Pakawatchai C, Papasergio RI, Patrick VA, White AH (1984) Lewis base adducts of Group IB metal(I) compounds. 9. Synthesis and crystal structures of adducts of copper(I) thiocyanate with substituted pyridine bases. Inorg Chem 23:3769–3776. doi: 10.1021/ic00191a021 CrossRefGoogle Scholar
  106. 106.
    Leydet Y, Bassani DM, Jonusauskas G, McClenaghan ND (2007) Equilibration between three different excited states in a bichromophoric copper(I) polypyridine complex. J Am Chem Soc 129:8688–8689. doi: 10.1021/ja072335n CrossRefGoogle Scholar
  107. 107.
    Mara MW, Jackson NE, Huang J, Stickrath AB, Zhang X, Gothard NA, Ratner MA, Chen LX (2013) Effects of electronic and nuclear interactions on the excited-state properties and structural dynamics of copper(I) diimine complexes. J Phys Chem B 117:1921–1931. doi: 10.1021/jp311643t CrossRefGoogle Scholar
  108. 108.
    Shaw GB, Grant CD, Shirota H, Castner EW, Meyer GJ, Chen LX (2007) Ultrafast structural rearrangements in the MLCT excited state for copper(I) bis- phenanthrolines in solution. J Am Chem Soc 129:2147–2160. doi: 10.1021/ja067271f CrossRefGoogle Scholar
  109. 109.
    Huang J, Mara MW, Stickrath AB, Kokhan O, Harpham MR, Haldrup K, Shelby ML, Zhang X, Ruppert R, Sauvage J-P, Chen LX (2014) A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a Cu I -diimine complex captured by X-ray transient absorption spectroscopy. Dalt Trans 43:17615–17623. doi: 10.1039/C4DT02046D CrossRefGoogle Scholar
  110. 110.
    Iwamura M, Takeuchi S, Tahara T (2014) Substituent effect on the photoinduced structural change of Cu(i) complexes observed by femtosecond emission spectroscopy. Phys Chem Chem Phys 16:4143. doi: 10.1039/c3cp54322f CrossRefGoogle Scholar
  111. 111.
    Iwamura M, Takeuchi S, Tahara T (2007) Real-time observation of the photoinduced structural change of bis(2,9-dimethyl-1,10-phenanthroline)copper(I) by femtosecond fluorescence spectroscopy: a realistic potential curve of the Jahn-Teller distortion. J Am Chem Soc 129:5248–5256. doi: 10.1021/ja069300s CrossRefGoogle Scholar
  112. 112.
    Zink DM, Volz D, Bergmann L, Nieger M, Bräse S, Yersin H, Baumann T (2013) Novel oligonuclear copper complexes featuring exciting luminescent characteristics. In: So F, Adachi C (eds) Proceedings of SPIE. pp 882907–1–882907–17Google Scholar
  113. 113.
    Bergmann L, Hedley GJ, Baumann T, Bra se S, Samuel IDW (2016) Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state. Sci Adv 2:e1500889. doi: 10.1126/sciadv.1500889 CrossRefGoogle Scholar
  114. 114.
    Gothard NA, Mara MW, Huang J, Szarko JM, Rolczynski B, Lockard JV, Chen LX (2012) Strong steric hindrance effect on excited state structural dynamics of Cu(I) diimine complexes. J Phys Chem A 116:1984–1992. doi: 10.1021/jp211646p CrossRefGoogle Scholar
  115. 115.
    Iwamura M, Takeuchi S, Tahara T (2015) Ultrafast excited-state dynamics of copper(I) complexes. Acc Chem Res 48:782–791. doi: 10.1021/ar500353h CrossRefGoogle Scholar
  116. 116.
    Chen LX, Shaw GB, Novozhilova I, Liu T, Jennings G, Attenkofer K, Meyer GJ, Coppens P (2003) MLCT state structure and dynamics of a copper(I) diimine complex characterized by pump-probe X-ray and laser spectroscopies and DFT calculations. J Am Chem Soc 125:7022–7034. doi: 10.1021/ja0294663 CrossRefGoogle Scholar
  117. 117.
    Volz D, Wallesch M, Grage SL, Göttlicher J, Steininger R, Batchelor D, Vitova T, Ulrich AS, Heske C, Weinhardt L, Baumann T, Bräse S (2014) Labile or stable: can homoleptic and heteroleptic PyrPHOS-copper complexes be processed from solution? Inorg Chem 53:7837–7847. doi: 10.1021/ic500135m CrossRefGoogle Scholar
  118. 118.
    Wallesch M, Bräse S, Baumann T, Volz D (2015) X-ray absorption spectroscopy: towards more reliable models in material sciences. In: So F, Adachi C, Kim J-J (eds) Proceedings of SPIE. p 956609Google Scholar
  119. 119.
    Liu Z, Qiu J, Wei F, Wang J, Liu X, Helander MG, Rodney S, Wang Z, Bian Z, Lu Z, Thompson ME, Huang C (2014) Simple and high efficiency phosphorescence organic light-emitting diodes with codeposited copper(I) emitter. Chem Mater 26:2368–2373. doi: 10.1021/cm5006086 CrossRefGoogle Scholar
  120. 120.
    Ni T, Liu X, Zhang T, Bao H, Zhan G, Jiang N, Wang J, Liu Z, Bian Z, Lu Z, Huang C (2015) Red emissive organic light-emitting diodes based on codeposited inexpensive Cu(I) complexes. J Mater Chem C 3:5835–5843. doi: 10.1039/C5TC00727E CrossRefGoogle Scholar
  121. 121.
    Liu Z, Qayyum MF, Wu C, Whited MT, Djurovich PI, Hodgson KO, Hedman B, Solomon EI, Thompson ME (2011) A codeposition route to Cu(I)-pyridine coordination complexes for organic light-emitting diodes. J Am Chem Soc 133:3700–3703. doi: 10.1021/ja1065653 CrossRefGoogle Scholar
  122. 122.
    Liu Z, Qayyum MF, Wu C, Whited MT, Djurovich PI, Hodgson KO, Hedman B, Solomon EI, Thompson ME (2011) A codeposition route to Cu(I)—pyridine coordination complexes for organic light-emitting diodes. J Am Chem Soc 133:3700–3703. doi: 10.1021/ja1065653 CrossRefGoogle Scholar
  123. 123.
    Zhang S, Turnbull GA, Samuel IDW (2012) Highly efficient solution-processable europium-complex based organic light-emitting diodes. Org Electron 13:3091–3096. doi: 10.1016/j.orgel.2012.09.006 CrossRefGoogle Scholar
  124. 124.
    Kau LS, Spira-Solomon DJ, Penner-Hahn JE, Hodgson KO, Solomon EI (1987) X-ray absorption edge determination of the oxidation state and coordination number of copper. Application to the type 3 site in Rhus vernicifera laccase and its reaction with oxygen. J Am Chem Soc 109:6433–6442. doi: 10.1021/ja00255a032 CrossRefGoogle Scholar
  125. 125.
    Pickering IJ, George GN, Dameron CT, Kurz B, Winge DR, Dance IG (1993) X-ray absorption spectroscopy of cuprous-thiolate clusters in proteins and model systems. J Am Chem Soc 115:9498–9505. doi: 10.1021/ja00074a014 CrossRefGoogle Scholar
  126. 126.
    Volz D, Baumann T, Flügge H, Mydlak M, Grab T, Bächle M, Barner-Kowollik C, Bräse S (2012) Auto-catalysed crosslinking for next-generation OLED-design. J Mater Chem 22:20786. doi: 10.1039/c2jm33291d CrossRefGoogle Scholar
  127. 127.
    Sato T, Uejima M, Kaji H, Tanaka K, Adachi C (2014) A light-emitting mechanism for organic light-emitting diodes: molecular design for inverted singlet-triplet structure and symmetry-controlled thermally activated delayed fluorescence. J Mater Chem C 00:1–9. doi: 10.1039/C4TC02320J Google Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Institute of Toxicology and Genetics, Karlsruhe Institute of TechnologyKarlsruheGermany
  2. 2.CYNORA GmbHBruchsalGermany
  3. 3.Institute of Organic ChemistryKarlsruhe Institute of TechnologyKarlsruheGermany

Personalised recommendations