Pyridinylphosphorothioate-based blue iridium(iii ) complex with double chiral centers for circularly polarized electroluminescence
| Autor: | Xiao Liang, Zhen-Long Tu, Zhong-Ze Qu, Yi-Pin Zhang, You-Xuan Zheng, Zheng-Guang Wu, Xu-Feng Luo, Jun-Jian Lu |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Journal of Materials Chemistry C. 9:5244-5249 |
| ISSN: | 2050-7534 2050-7526 |
| Popis: | Circularly polarized organic light-emitting diodes (CP-OLEDs) have received considerable attention due to their promising applications in 3D displays. However, up to now, CP-OLEDs using iridium(III) phosphors as emissive dopants exhibited low brightness, insufficient efficiency, serious efficiency roll-off, and especially low electroluminescence dissymmetry factors (gEL). In this study, a blue Ir(III) complex Ir(dfppy)2(sdpp) (dfppy is 2-(2,4-difluorophenyl)pyridine, sdpp is pyridinylphosphorothioate) peaking at 466 nm was synthesized, and two pairs of enantiomers containing the λ or δ isomer together with a chiral phosphine center (R or S) were separated into λ-Ir(dfppy)2(S-sdpp), δ-Ir(dfppy)2(R-sdpp), λ-Ir(dfppy)2(R-sdpp) and δ-Ir(dfppy)2(S-sdpp), respectively. It is the first example to investigate phosphine chirality in an Ir(III) complex, and the electron cloud distribution in the chiral conjugated ancillary ligand and λ/δ chirality of the Ir(III) center induced Ir(dfppy)2(sdpp) to exhibit decent circularly polarized luminescence (CPL) activities with a dissymmetry factor (|gPL|) around 1.4 × 10−3. The OLEDs based on Ir(dfppy)2(sdpp) exhibited a maximum external quantum efficiency of 13.8% with mild efficiency roll-off. Notably, the CP-OLEDs based on λ-Ir(dfppy)2(S-sdpp), δ-Ir(dfppy)2(R-sdpp), λ-Ir(dfppy)2(R-sdpp) and δ-Ir(dfppy)2(S-sdpp) showed obvious circularly polarized electroluminescence (CPEL) signals with a gEL of −2.1 × 10−3, 2.4 × 10−3, −2.1 × 10−3 and 1.9 × 10−3, respectively, thus affording an efficient strategy for the design of chiral blue Ir(III) emitters and their CP-OLEDs. |
| Databáze: | OpenAIRE |
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