Kim Yoseph, Kim Jaehoon, Lee Ji Hye, Moon Hyeongkwon, Noh Ga Hee, Hwang Hyonseok, Lee Junseong, Park Jun Hui, Kim Youngjo, Park Myung Hwan
Department of Chemistry and BK21+ Program Research Team, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
Department of Chemistry Education, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
Dalton Trans. 2023 Sep 26;52(37):13379-13386. doi: 10.1039/d3dt02129g.
Herein, we report our findings on 4-carbazole (CBZ)-appended salen-based indium complexes, CBZIn1 and CBZIn2, which feature diimine bridges exhibiting different electron-accepting properties. Notably, CBZIn2 exhibited a significantly higher photoluminescence quantum efficiency (PLQY, ) in toluene than CBZIn1, with a value over 15 times greater ( = 57.7% for CBZIn2; = 3.7% for CBZIn1). In particular, in the rigid state of THF at 77 K, CBZIn2 exhibited a near-unity PLQY of 98.2%. Even in the PMMA film, CBZIn2 maintained a high level of PLQY ( = 70.2%). These results can be attributed to the highly efficient radiative decay process based on intramolecular charge-transfer (ICT) transition between the moderately twisted CBZ, characterized by its conformational rigidity and the 1,2-dicyanoethylene-bridged salen, which exhibits a strong electron-accepting ability. Furthermore, these findings are supported by theoretical calculations.
