化学学报 ›› 2020, Vol. 78 ›› Issue (1): 56-62.DOI: 10.6023/A19110406 上一篇    下一篇

研究论文

含螺环位阻铱(III)配合物的共轭结构调控及其电致发光性能研究

任保轶a, 依建成a, 钟道昆a, 赵玉志a, 郭闰达c, 盛永刚a,b, 孙亚光a, 解令海b, 黄维b   

  1. a 沈阳化工大学 应用化学学院 辽宁省无机分子基化学重点实验室 沈阳 110142;
    b 南京邮电大学 江苏省有机电子与信息显示重点实验室-省部共建国家重点实验室培育基地 南京 210023;
    c 华中科技大学 武汉光电国家研究中心 武汉 430074
  • 收稿日期:2019-11-15 出版日期:2020-01-15 发布日期:2019-12-20
  • 通讯作者: 郭闰达, 孙亚光 E-mail:runda_guo@hust.edu.cn;sunyaguang@syuct.edu.cn
  • 基金资助:
    项目受辽宁省高等学校创新人才支持计划(LR2018018)、辽宁省自然科学基金(No.20180550539)、沈阳市科学技术计划项目(No.18-013-0-26)和江苏省有机电子与信息显示重点实验室—省部共建国家重点实验室培育基地开放研究基金资助.

Conjugated Regulation of Phosphorescent Iridium (III) Complex Constructed from Spiro Ligand and Its Electroluminescent Performances

Ren Bao-Yia, Yi Jian-Chenga, Zhong Dao-Kuna, Zhao Yu-Zhia, Guo Run-Dac, Sheng Yong-Ganga,b, Sun Ya-Guanga, Xie Ling-Haib, Huang Weib   

  1. a Key Laboratory of Inorganic Molecule-Based Chemistry of Liaoning Province, College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang 110142;
    b Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials(IAM), Nanjing University of Posts & Telecommunications, Nanjing 210023;
    c Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074
  • Received:2019-11-15 Online:2020-01-15 Published:2019-12-20
  • Supported by:
    Project supported by the Supporting Project for Innovative Talents of Higher Education Institutions in Liaoning Province (LR2018018), the Natural Science Foundation of Liaoning Province (No. 20180550539), the Science and Technology project of Shenyang (No. 18-013-0-26), and the Open Research Fund of Key Laboratory for Organic Electronics and Information Displays.

基于螺[芴-9,9'-氧杂蒽]的位阻结构,在其芴端连接苯并噻唑构成共轭扩展的环金属配体,并成功合成了相应的均配、面式构型铱(III)配合物fac-Ir(SFXbtz)3.配合物的最强发射峰位于587 nm,在635 nm处伴有肩峰发射;其在溶液中的磷光寿命为316 ns,光致发光量子产率达到64.7%.以fac-Ir(SFXbtz)3为发射材料,在高掺杂浓度下分别制备了橙光电致发光器件及与蓝光材料FIrpic(双(4,6-二氟苯基吡啶-NC2)吡啶甲酰合铱)组合的二元白光器件.以CBP(4,4'-二(9-咔唑)联苯)为主体材料的橙光器件最高电流效率和功率效率为10.8 cd·A-1和8.4 lm·W-1,最大亮度为7217 cd·m-2.二元白光器件最高电流效率和功率效率为11.6 cd·A-1和8.0 lm·W-1,最大亮度为8763 cd·m-2,在3~9 V操作电压下CIE1931色坐标稳定.结果表明:协同利用螺环芳烃的共轭结构和位阻结构优势,是获得低成本、本征光电性质良好及可高浓度掺杂的磷光铱(III)配合物的便捷方法.

关键词: 螺[芴-9,9'-氧杂蒽], 环金属铱(III)配合物, 共轭结构, 电致发光

It is an important pathway in the field of phosphorescent organic light-emitting diodes (PhOLED) that endowing iridium (III) emitters with the features of low-cost, decent photoelectric properties, and high doping-concentration application by harmonizing electronic and steric effects of corresponding ligands. Based on our previous research that introducing spiro ligand into IrIII complexes to protect emitting-center and to suppress concentration quenching, herein, for pushing the emission to orange region, we extend the conjugated structure of spiro[fluorene-9,9'-xanthene] (SFX) by connected benzo[d]-thiazole-2-yl on the fluorene moiety of SFX via Suzuki-Miyaura coupling, acting as a new spiro ligand. A homoleptic IrIII complex, fac-Ir(SFXbtz)3, was synthesized successfully, and the structure and the photophysical and electrochemical properties were studied by nuclear magnetic resonance, single crystal X-ray diffraction, absorption and emission measurements, as well as cyclic voltammetry. The crystallographic data revealed an enlarged Ir…Ir distance and weakly intermolecular π-π interactions between the spiro ligands. The emission spectrum of fac-Ir(SFXbtz)3 showed a maximum peak at 587 nm and a shoulder peak at 635 nm with a photoluminescence (PL) quantum yield (QY) of 64.7% (relative to tris[2-phenylpyridinato-C2,N]iridium(III), PLQY=40%). The highest occupied molecular orbital level was determined to be -5.28 eV according to the onset oxidation potential (0.48 V). In view of the orange light-emitting and the high PLQY of fac-Ir(SFXbtz)3, the monochromatic and two-element white PhOLED were fabricated to investigate its electroluminescence (EL) performance in high doping concentrations, ω=12% for monochromatic device and ω=15% for two-element white device, respectively. The EL spectrum of the monochromatic PhOLED (device D1) using common 4,4'-bis(N-carbazolyl)-1,1'-biphenyl as host exhibits two emission peaks, a maximum emission peak at 581 nm and shoulder emission peak at 631 nm, corresponding to its PL spectrum. The device D1 shows a peak performance of 10.8 cd·A-1 and 8.4 lm·W-1, maximum brightness of 7217 cd·m-2, respectively. The two-element white PhOLED selecting bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) as complementary blue-light component, possesses a peak performance of 11.6 cd·A-1 and 8.0 lm·W-1, maximum brightness of 8763 cd·m-2, and stabilized CIE 1931 (0.34~0.37, 0.36~0.38) under operated voltages of 3~9 V, respectively. These results indicate that the fac-Ir(SFXbtz)3 is a potential phosphor for efficient orange PhOLED, possessing the advantages of low-cost, suitable doping in high concentration, and stabilized color coordinates.

Key words: spiro[fluorene-9,9'-xanthene], cyclometalated iridium (III) complex, conjugated structure, electroluminescence