CRCU

Chemical Research in Chinese Universities ›› 2012, Vol. 28 ›› Issue (4): 572-576.

• Articles • Previous Articles     Next Articles

Novel Iridium Complex with Carbazol-2-yl-β-diketone Derivative: Low-energy Excitation and Red Electrophosphorescent Devices

LIU Jian1, CHEN Hong-bin2, LIU Sheng-gui 3   

  1. 1. School of New Energy Science and Engineering, Xinyu University, Xinyu 338004, P. R. China;
    2. Physics Department, Information College, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, P. R. China;
    3. School of Chemistry Science and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
  • Received:2011-08-01 Revised:2011-09-28 Online:2012-07-25 Published:2012-07-25
  • Supported by:

    Supported by the Natural Science Foundation of Guangdong Province, China(No.10152404801000017).

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Abstract: A novel iridium-complex, (BPPBI)2Ir(2-TFDBC)[BPPBI=2-(biphenyl-4-yl)-1-phenyl-1H-benzo[d]imi- dazole, 2-TFDBC=1-(9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione], was synthesized, and its structure and component were confirmed by 1H NMR and element analysis, respectively. UV-Vis absorption and photoluminescent(PL) spectra of (BPPBI)2Ir(2-TFDBC) in dichloromethane were investigated. The Ir-complex exhibited a long wavelength excitation of 470 nm, i.e., low-energy excitation. So, it is a promising candidate for phosphorescent probe and PL material. (BPPBI)2Ir(2-TFDBC)-based electroluminescent devices, ITO/MoO3(10 nm)/NPB(80 nm)/ CBP:x(BPPBI)2Ir(2-TFDBC)(20 nm)/TPBi(45 nm)/LiF/Al, were fabricated, where x(%) was of 4% or 8% doping concentration(mass fraction); ITO=indium tin oxides; NBP=N,N'-bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)- 4,4'-diamine, CBP=4,4'-bis(N-carbazolyl)-1,1'-biphenyl, TPBi=1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene. The devices showed a red emission of 620 nm. The maximum current efficiency and brightness were 1.7 cd/A and 4063 cd/m2 for a device of 8%(mass fraction) doping level, respectively. The moderate luminous efficiency was due to the inadequate energy transfer from the host material to the guest material.

Key words: Iridium complex, Low-energy excitation, Red electrophosphorescent device