High performance asymmetrical push–pull small molecules end-capped with cyanophenyl for solution-processed solar cells†
Abstract
Two novel asymmetrical push–pull small molecules have been synthesized successfully, consisting of triphenylamine and diketopyrrolopyrrole as a fundamental dipolar D–π–A structure with ethynylbenzene as the π-bridge. TPATDPPCN end-capped with cyanophenyl exhibits a low optical band gap of 1.65 eV, and an impressive PCE of 5.94% has been achieved.