Skip to main content
SpringerLink
Log in

Heat revolution on photophysical properties and electroluminescent performance of Ir(ppy)3-doped bipolar host of oxadiazole derivatives attaching with inert group of tert-butyl moiety

  • Articles
  • Published:
Science China Chemistry Aims and scope Submit manuscript

Abstract

Two bipolar materials, 2,5-bis(2-(9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole (o-CzOXD) and 2,5-bis(2-(3′,6′-di-tert-butyl-9H-carbazole-9-yl)phenyl)-1,3,4-oxadiazole (tBu-o-CzOXD), were synthesized according to reported methods. In parallel study, it was demonstrated that introduction of inert tert-butyl group improved material thermal stability, even though this modification only had a slight influence to the photophysical and electrochemical properties of these materials. A comparative study focusing on effects of heat treatment was carried out on the quartz glass substrates with vacuum deposited films containing one of the bipolar host doped with 6 wt% fac-tris(2-phenylpyridinato-N,C2′)iridium (Ir(ppy)3). Results show that when the two samples were heated, the absorption, emission, and photo images of the host:dopant system changed, with the o-CzOXD suffering more severe degradation under high temperature, which is consistent with their thermal stability. In addition, it was proved that the high temperature-annealed host:dopant system can enhance the emission of the dopant. This finding was used as a guideline to improve our device performance. We fabricated two types of phosphorescent organic light-emitting devices (PhOLEDs), one was based on o-CzOXD, the other was based on tBu-o-CzOXD. They had analogous structure. We investigated the effect of heat on device performance by selectively annealing. Although these two freshly prepared devices exhibited similar performance, when annealed at 90 °C for 10 minutes, the OLEDs based on tBu-o-CzOXD showed significant performance enhancement, which can be attributed to the observation that annealing Ir(ppy)3 doped host can change film morphology and enhance the dopant emission. The maximum efficiencies of the freshly prepared tBu-o-CzOXD device were 25.8 cd A−1, 23.1 lm W−1, and 9.3%; whereas those for annealed device were 47.0 cd A−1, 42.2 lm W−1, and 13.4%.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Tang CW, Vanslyke SA. Organic electroluminescent diodes. Appl Phys Lett, 1987, 51: 913–915

    Article  CAS  Google Scholar 

  2. Baldo MA, O’Brien DF, You Y, Shoustikov A, Sibley S, Thompson ME, Forrest SR. Highly efficient phosphorescent emission from organic electroluminescent devices. Nature, 1988, 395: 151–154

    Google Scholar 

  3. Baldo MA, Lamansky S, Burrows PE, Thompson ME, Forrest SR. Very high-efficiency green organic light-emitting devices based on electrophosphorescence. Appl Phys Lett, 1999, 75: 4–6

    Article  CAS  Google Scholar 

  4. Adachi C, Baldo MA, Thompson ME, Forrest SR. Nearly 100% internal phosphorescence efficiency in an organic light-emitting device. J Appl Phys, 2011, 90: 5048–5051

    Article  Google Scholar 

  5. Lamansky S, Djurovich P, Murphy D, Abdel-Razzaq F, Lee HE, Adachi C, Burrow PE, Forrest SR, Thompson ME. Highly phosphorescent bis-cyclometalated iridium complexs: Synthesis, photophysical characterization, and use in organic light emitting diodes. J Am Chem Soc, 2001, 123: 4304–4312

    Article  CAS  Google Scholar 

  6. Baldo MA, Adachi C, Forrest SR. Transient analysis of organic electrophosphorescence. II. Transient analysis of triplet-triplet annihilation. Phys Rev B, 2000, 62: 10967–10977

    Article  CAS  Google Scholar 

  7. Mi BX, Gao ZQ, Lee CS, Lee ST. Reduction of molecular aggregation and its application to the high-performance blue perylene-doped organic electroluminescent device. Appl Phys Lett, 1999, 75: 4055–4057

    Article  CAS  Google Scholar 

  8. Tokito S, Iijima T, Suzuki Y, Kita H, Tsuzuki T, Sato F. Confinement of triplet energy on phosphorescent molecules for highly-efficient organic blue-light-emitting device. Appl Phys Lett, 2003, 83: 569–571

    Article  CAS  Google Scholar 

  9. Holmes RJ, Forrest SR, Tung YJ, Kwong RC, Brown JJ, Garon S, Thompson ME. Blue organic electrophosphorescence using exothermic host-guest energy transfer. Appl Phys Lett, 2003, 82: 2422–2424

    Article  CAS  Google Scholar 

  10. Chou HH, Cheng CH. A highly efficient universal bipolar host for blue, green, and red phosphorescent OLEDs. Adv Mater, 2010, 22: 2468–2471

    Article  CAS  Google Scholar 

  11. Hughes G, Bryce MR. Electron-transporting materials for organic electroluminescent and electrophosphorescent devices. J Mater Chem, 2005, 15: 94–107

    Article  CAS  Google Scholar 

  12. Lundin NJ, Blackman AG, Gordon KC, Officer DL. Synthesis and characterization of a multicomponent rhenium(I) complex for application as an OLED dopant. Angew Chem Int Ed, 2006, 45: 2582–2584

    Article  CAS  Google Scholar 

  13. Tokito S, Tanaka H, Okada A, Taga Y. High-temperature operation of an electroluminescent device fabricated using a novel triphenylamine derivative. Appl Phys Lett, 1996, 69: 878–880

    Article  CAS  Google Scholar 

  14. Tokoto S, Noda K, Fujikawa H, Taga Y, Kimura M, Shimada K, Sawaki Y. highly efficient blue-green emission from organic light-emitting diodes using dibenzochrysene derivatives. Appl Phys Lett, 2000, 77: 160–162

    Article  Google Scholar 

  15. Mi BX, Gao ZQ, Liao ZJ, Huang W, Chen CH. Molecular hosts for triplet emitters in organic light-emitting diodes and the corresponding working principle. Sci China Chem, 2010, 53: 1679–1694

    Article  CAS  Google Scholar 

  16. Xiao LX, Chen ZJ, Qu B, Luo JX, Kong S, Gong QH, Kido J. Recent progresses on materials for electro phosphorescent organic light-emitting devices. Adv Mater, 2011, 23: 926–952

    Article  CAS  Google Scholar 

  17. Tao YT, Yang CL, Qin JG. Organic host materials for phosphorescent organic light-emitting diodes. Chem Soc Rev, 2011,40: 2943–2970

    Article  CAS  Google Scholar 

  18. Zhang K, Liu SJ, Guan X, Duan CH, Zhang J, Zhong CM, Wang L, Huang F, Cao Y. Alkali metal salts doped pluronic block polymers as electron injection/transport layers for high performance polymer light-emitting diodes. Sci China Chem, 2012, 55: 766–771

    Article  CAS  Google Scholar 

  19. Yu ZB, Li L, Gao HE, Pei QB. Polymer light-emitting electrochemical cells: Recent developments to stabilize the p-i-n junction and explore novel device applications. Sci China Chem, 2013, 56: 1075–1086

    Article  CAS  Google Scholar 

  20. Liu SJ, Zhang ZP, Chen DC, Duan CH, Lu JM, Zhang J, Huang F, Su SJ, Chen JW, Cao Y. Synthesis and optoelectronic properties of amino-functionalized carbazole-based conjugated polymers. Sci China Chem, 2013, 56: 1119–1128

    Article  CAS  Google Scholar 

  21. Liu ZT, Hu SJ, Zhang LH, Chen JW, Peng JB, Cao Y. Electroluminescence performances of 1,1-bis(4-(N,N-dimethylamino)phenyl)-2, 3,4,5-tetraphenylsilole based polymers in three cathode architectures. Sci China Chem, 2013, 56: 1129–1136

    Article  CAS  Google Scholar 

  22. Yu JT, Wu XG, Tan H, Liu Y, Wang YF, Zhu MX, Zhu WG. High-efficiency saturated red emission from binuclear cyclo-metalated platinum complex containing 5-(4-octyloxyphenyl)-1,3,4-oxadiazole-2-thiol ancillary ligand in PLEDs. Sci China Chem, 2013, 56: 1137–1142

    Article  CAS  Google Scholar 

  23. Hung WY, Chi LC, Chen WJ, Mondal E, Chou SH, Wong KT, Chi Y. A carbazole-phenylbenzimidazole hybrid bipolar universal host for high efficiency RGB and white PhOLEDs with high chromatic stability. J Mater Chem, 2011, 21: 19249–19256

    Article  CAS  Google Scholar 

  24. Hung WY, Tu GM, Chen SW, Chi Y. Phenylcarbazole-dipyridyl triazole hybrid as bipolar host material for phosphorescent OLEDs. J Mater Chem, 2012, 22: 5410–5418

    Article  CAS  Google Scholar 

  25. Ding JQ, Wang Q, Zhao L, Ma DG, Wang LX, Jing XB, Wang FS. Design of star-shaped molecular architectures based on carbazole and phosphine oxide moieties: Towards amorphous bipolar hosts with high triplet energy for efficient blue electrophosphorescent devices. J Mater Chem, 2010,20: 8126–8133

    Article  CAS  Google Scholar 

  26. Gao ZQ, Luo MM, Sun XH, Tam HL, Wong MS, Mi BX, Xia PF, Cheah KW, Chen CH. New host containing bipolar carrier transport moiety for high-efficiency electrophosphorescence at low voltages. Adv Mater, 2009, 21: 688–692

    Article  Google Scholar 

  27. Huang H, Wang YX, Zhuang SQ, Yang X, Wang L, Yang CL. Simple phenanthroimidazole/carbazole hybrid bipolar host materials for highly efficient green and yellow phosphorescent organic light-emitting diodes. J Phys Chem C, 2012, 116: 19458–19466

    Article  CAS  Google Scholar 

  28. Tao YT, Wang Q, Yang CL, Wang Q, Zhang ZQ, Zou TT, Qin JG, Ma DG. A simple carbazole/oxadiazole hybrid molecule: An excellent bipolar host for green and red phosphorescent OLEDs. Angew Chem Int Ed, 2008, 47: 8104–8107

    Article  CAS  Google Scholar 

  29. Tao YT, Gong SL, Wang Q, Zhong C, Yang CL, Qin JG, Ma DG. Morphologically and electrochemically stable bipolar host for efficient green electrophosphorescence. Phys Chem Chem Phys, 2010, 12: 2438–2442

    Article  CAS  Google Scholar 

  30. Ho MH, Balaganesan B, Chu TY, Chen TM, Chen CH. A morphologically stable host material for efficient phosphorescent green and red organic light emitting devices. Thin Solid Films, 2008, 517: 943–947

    Article  CAS  Google Scholar 

  31. Wu MF, Yeh SJ, Chen CT, Murayama H, Tsuboi T, Li WS, Chao I, Liu SW, Wang JK. The quest for high-performance host materials for electrophosphorescent blue dopants. Adv Funct Mater, 2007, 17: 1887–1895

    Article  CAS  Google Scholar 

  32. Okamoto S, Tanaka K, Izumi Y, Adachi H, Yamaji T, Suzuki T. Simple measurement of quantum efficiency in organic electroluminescent devices. Jpn J Appl Phys, 2001, 40: 783–787

    Article  Google Scholar 

  33. Zhu ZG, Moore JS. Synthesis and characterization of monodendrons based on 9-phenylcarbazole. J Org Chem, 2000, 65: 116–123

    Article  CAS  Google Scholar 

  34. Mcclenaghan ND, Passalacqua R, Loiseau F, Campagna S, Verheyde B, Hameurlaine A, Dehaen W. Ruthenium(II) dendrimers containing carbazole-based chromophores as branches. J Am Chem Soc, 2003, 125: 5356–5365

    Article  Google Scholar 

  35. Please be noticed that in the reduction curves of the two compounds, the firstly appeared redoxes originate from solvent of THF as confirmed by THF blank sample.

  36. Tokito S, Tanaka H, Noda K, Okada A, Taga Y. Thermal stability in oligomeric triphenylamine/tris(8-quinolinolato) aluminum electroluminescent devices. Appl Phys Lett, 1997, 70: 1929–1931

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Jiangsu Engineering Centre for Flat-Panel Displays & Solid-state Lighting, College of Materials Science & Engineering, Nanjing University of Posts & Telecommunications, Nanjing, 210046, China

    HongJiao Wang, Chen Liu, BaoXiu Mi & Jie Sang

  2. Key Laboratory for Organic Electronics & Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing, 210046, China

    HongJiao Wang, Chen Liu, Xin Li & ZhiQiang Gao

Authors
  1. HongJiao Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Chen Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. BaoXiu Mi
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Jie Sang
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Xin Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. ZhiQiang Gao
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding authors

Correspondence to BaoXiu Mi or ZhiQiang Gao.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Wang, H., Liu, C., Mi, B. et al. Heat revolution on photophysical properties and electroluminescent performance of Ir(ppy)3-doped bipolar host of oxadiazole derivatives attaching with inert group of tert-butyl moiety. Sci. China Chem. 57, 849–856 (2014). https://doi.org/10.1007/s11426-013-5015-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11426-013-5015-5

Keywords

Search

Navigation