Synthesis and properties study of cyano-modified carbazole-phenanthroimidazole-based blue light emitting molecules

In this paper, based on the D-π-A structure model, carbazole and phenimidazole groups were used as the building blocks of blue molecules, and p-aminobenzonitrile and m-aminobenzonitrile were added to the N (1) position of imidazole, respectively. Synthesized two novel blu-ray molecular 4 - (2 - (4 ’- (3, 6-2 tertiary butyl - 9 h - carbazole - 9 - base) - [1, 1’ - biphenyls] - 4 - base) 1 h - fe and [9, 10 - d] imidazole - 1 - base) phenyl nitrile (NCPPIM - CzBu 1) and 3 - (2 - (4 ’- (3, 6-2 tertiary butyl - 9 h - carbazole - 9 - base) - [1, 1’ - biphenyls] - 4 -) 1 h - fe and imidazole [9, 10 - d] - 1 - base) phenyl nitrile (NCPPIM - CzBu 2). The experimental results showed that the cyanoide-linked molecule (NCPPIM-CzBu 2) exhibited higher T g and fluorescence quantum yield than the cyanoide-para-linked molecule (NCPPIM-CzBu 1). The fluorescence quantum yield of NCPPIM-CzBu 2 is 49 % higher than that of NCPPIM-CzBu 1. It shows that the proper selection of para-position and intersite of cyanogen groups plays an important role in the synthesis of blue molecules with good properties, and provides a new way for the synthesis of novel blue molecules.