Effects of end groups on crystallinity, optoelectrical properties and performance of organic solar cells in noncovalently-fused backbone small molecule acceptors

Abstract

In this contribution, I investigated the effects of end-groups in Noncovalently-fused backbone small molecule electron acceptors on crystallinity, optoelectrical properties and performance of organic solar cells. The small molecule electron acceptors were synthesized with different end-groups and called Triazole-IC, Triazole-ICBr and Triazole-IC2Cl whose end-groups were hydrogen, monobromine and dichlorine atom. Introducing halogen atoms were expected to develop dipole moment within molecular structure which increase intermolecular interaction between them and enhance optoelectrical properties. The Triazole-IC4Cl showed improved molecular properties among other acceptors and those directly influenced on the performance of the organic solar cell devices. As a result, the device fabricated with Triazole-IC4Cl acceptor enable the maximum power conversion efficiency (PCE) of 9.22%. Thus, noncovalent interaction strategy can be effective approach to design small molecule acceptors.