Acta Chimica Sinica ›› 2013, Vol. 71 ›› Issue (06): 884-891.DOI: 10.6023/A13010113 Previous Articles     Next Articles



史清华a,b, 彭谦b, 孙少瑞a, 帅志刚b,c   

  1. a 北京工业大学环境与能源工程学院 北京 100124;
    b 中国科学院化学研究所 北京分子科学国家实验室 有机固体院重点实验室 北京 100190;
    c 清华大学化学系 有机光电子与分子工程重点实验室 北京 100084
  • 投稿日期:2013-01-22 发布日期:2013-03-26
  • 通讯作者: 孙少瑞,;帅志刚,;
  • 基金资助:

    项目受国家自然科学基金(Nos. 21290190, 91233105)和科技部973项目(Nos. 2009CB623600, 2013CB834703)资助.

Vibration Correlation Function Investigation on the Phosphorescence Quantum Efficiency and Spectrum for Blue Phosphorescent Ir(III) Complex

Shi Qinghuaa,b, Peng Qianb, Sun Shaoruia, Shuai Zhigangb,c   

  1. a College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124;
    b Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190;
    c Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084
  • Received:2013-01-22 Published:2013-03-26
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21290190, 91233105) and the Ministry of Science and Technology of China through 973 Program (Nos. 2009CB623600, 2013CB834703).

A challenging issue for white organic light-emitting diodes is to improve the luminescence efficiency and stability for blue phosphorescence materials. In order to deeper understand the relationship between molecular structure and luminescence quantum efficiency, we apply our recently developed correlation function method coupled with density functional theory calculation to investigate the photophysical properties of fac-tris(2-(4,6-difluorophenyl)pyridyl iridium (fac-Ir(F2ppy)3), including phosphorescence emission spectra, radiative and nonradiative decay rates, and excited-state decay lifetime at different temperatures. All the calculated results can well reproduce the available experimental measurements. We further analyze the relevance of molecular parameters governing the photophysical processes. We found out that in fac-Ir(F2ppy)3: (1) when compared with the archetypal green fac-Ir(ppy)3, the introduction of F atoms can enlarge the energy gap between the excited triplet T1 and the ground state S0 resulting in blue-shift. This does not introduce extra reorganization energies in the excited-state relaxation process. So the blue phosphorescent fac-Ir(F2ppy)3 can exhibit high luminescence efficiency; (2) the main channels for nonradiatively dissipating the electronic excited-state energy are found to be the stretching vibrations of carbon and carbon bonds, such as C(5)—C(46) linking the fluorophenyl and pyridyl rings, C(43)—C(44) and C(42)—C(47) of pyridyl ring, and C(3)—C(6) of fluorophenyl ring in L1 ligand. This points out the direction for further increasing the light-emitting efficiency through suppressing these motions.

Key words: theory of intersystem crossing, molecular design of iridium (III) complex, phosphorescence spectrum, phosphorescence quantum efficiency