Insights into out-of-plane side chains effects on optoelectronic and photovoltaic properties of simple non-fused electron acceptors.

Non-fused ring electron acceptors with varied substituents were developed to construct efficient organic solar cells (OSCs). Out-of-plane rigid substituents such as 2-methylphenyl, 2- tert -butylphenyl and diphenylamine were introduced to the central benzene unit to improve the solubility of non-fused ring acceptors and noncovalent interactions such as O⋯S and N⋯S were used to enhance the planarity of molecular backbones. Blend films based on PBDB-T and these acceptors displayed better morphology without oversized aggregates formed. As-cast devices based on SM1 , SM2 and SM3 exhibited power conversion efficiencies of 5.96%, 6.43% and 6.80%, respectively. Image 1 • We designed three non-fused acceptors with varied substituents to construct efficient organic solar cells (OSCs). • Three electron acceptors could form strong intermolecular aggregations in films. • The morphology of blend films based on PBDB-T and acceptors displayed nanofibril network structure. • Simple non-fused acceptors are promising in achieving low-cost and high performance organic solar cells. [ABSTRACT FROM AUTHOR]