Zhu Ze-Lin, Gnanasekaran Premkumar, Yan Jie, Zheng Zhong, Lee Chun-Sing, Chi Yun, Zhou Xiuwen
Department of Materials Science and Engineering, Department of Chemistry, and Center of Super-Diamond Advanced Films, City University of Hong Kong, Kowloon Tong 999077, Hong Kong SAR, China.
Frontier Research Center on Fundamental and Applied Sciences of Matters and Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
Inorg Chem. 2022 Jun 13;61(23):8898-8908. doi: 10.1021/acs.inorgchem.2c01026. Epub 2022 May 30.
Four blue-emissive iridium(III) complexes bearing a 3,3'-(1,3-phenylene)bis[1-isopropyl-6-(trifluoromethyl)-3-imidazo[4,5-]pyridin-2-ylidene]-based pincer chelate, which are derived from PX·H(PF), where = 1-4, and a cyclometalating chelate given from 9-[6-[5-(trifluoromethyl)-2λ-pyrazol-3-yl]pyridin-2-yl]-9-carbazole [(PzpyCz)H], were successfully synthesized and employed as both an emissive dopant and a sensitizer in the fabrication of organic light-emitting diode (OLED) devices. These functional chelates around a Ir atom occupied two mutually orthogonal coordination arrangements and adopted the so-called bis-tridentate architectures. Theoretical studies confirmed the dominance of the electronic transition by the pincer chelates, while the dianionic PzpyCz chelate was only acting as a spectator group. Phosphorescent OLED devices with [Ir(PX3)(PzpyCz)] () as the dopant gave a maximum external quantum efficiency (EQE) of 21.93% and CIE of (0.144, 0.157) and was subjected to only ∼10% of roll-off in efficiency at a high current density of 1000 cd m. Blue-emissive narrow-band hyperphosphorescence was also obtained using as an assistant sensitizer and ν-DABNA as a terminal emitter, giving both an improved EQE of 26.17% and CIE of (0.116, 0.144), confirming efficient Förster resonance energy transfer in this hyperdevice.
四种带有基于3,3'-(1,3-亚苯基)双[1-异丙基-6-(三氟甲基)-3-咪唑并[4,5-]吡啶-2-亚基]的钳形螯合物的蓝色发光铱(III)配合物被成功合成，它们衍生自PX·H(PF)（其中 = 1 - 4）以及由9-[6-[5-(三氟甲基)-2λ-吡唑-3-基]吡啶-2-基]-9-咔唑[(PzpyCz)H]给出的环金属化螯合物，并被用作有机发光二极管(OLED)器件制造中的发光掺杂剂和敏化剂。围绕铱原子的这些功能性螯合物占据了两个相互正交的配位排列，并采用了所谓的双三齿结构。理论研究证实了钳形螯合物在电子跃迁中的主导地位，而二阴离子PzpyCz螯合物仅作为旁观者基团。以Ir(PX3)(PzpyCz)作为掺杂剂的磷光OLED器件的最大外量子效率(EQE)为21.93%，CIE为(0.144, 0.157)，并且在1000 cd m的高电流密度下效率仅下降约10%。使用作为辅助敏化剂和ν-DABNA作为末端发射体也获得了蓝色发光窄带超磷光，给出了提高的EQE为26.17%和CIE为(0.116, 0.144)，证实了在该超器件中有效的Förster共振能量转移。
