A push–pull organic semiconductor with efficient intramolecular charge transfer for solution-processed small molecule solar cells

Abstract

A new push–pull organic semiconductor, DMF-BP-T-MMN, containing a functionalized amine donor and a methylene malononitrile (MMN) acceptor has been designed and synthesized for use in solution-processable small molecule solar cells. This material exhibits superior intramolecular charge transfer from the functionalized amine group to MMN, which produces an electron-rich MMN group that facilitates electron transfer into the active layer constituent phenyl-C₇₁-butyric acid methyl ester in a solar cell. As a result, DMF-BP-T-MMN was found to exhibit excellent p-type semiconductor performance in an optimized organic solar cell: a power conversion efficiency of 3.40% with a high photocurrent density of 8.2 mA cm⁻².