Development of push-pull carbazole-based organic semiconductors with extended π-linkers for enhanced red-shifted absorption-emission and improved charge mobilities

This work presents the design and synthesis of a series of new organic semiconductors featuring a push-pull system, with two types of π-linkers with the different conjugation lengths between the electron-donating carbazole moiety and electron-withdrawing cyano groups. The findings provide insight into the role of conjugated π-linkers between donor and acceptor units in facilitating efficient charge transfer and tuning conjugation length. Compounds with the extended π-linker exhibit enhanced conjugation efficiency resulting in improved light absorption, red-shifted photoluminescence, and improved hole mobility. This study highlights the potential for design of organic semiconductors with tunable π-conjugation in push-pull systems for optoelectronic applications.