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

Translated title of the contribution: Conjugated Regulation of Phosphorescent Iridium (III) Complex Constructed from Spiro Ligand and Its Electroluminescent Performances

Bao Yi Ren, Jian Cheng Yi, Dao Kun Zhong, Yu Zhi Zhao, Run Da Guo, Yong Gang Sheng, Ya Guang Sun, Ling Hai Xie, Wei Huang

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

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.

Translated title of the contributionConjugated Regulation of Phosphorescent Iridium (III) Complex Constructed from Spiro Ligand and Its Electroluminescent Performances
Original languageChinese (Traditional)
Pages (from-to)56-62
Number of pages7
JournalActa Chimica Sinica
Volume78
Issue number1
DOIs
StatePublished - 15 Jan 2020
Externally publishedYes

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