Synergistic Effects Of Chlorination And Branched Alkyl Side Chain On The Photovoltaic Properties Of Simple Non-Fullerene Acceptors With Quinoxaline As The Core

To date, the fused-ring electron acceptors show the best photovoltaic performances, and the development of simple non-fullerene acceptors via intramolecular noncovalent interactions can reduce synthetic costs. In this work, four simple non-fullerene acceptors with an A-D-A'-D-A configuration (QCIC1, QCIC2, QCIC3, and QCIC4) were synthesized. They contained the same conjugated backbone (A': quinoxaline; D: cyclopentadithiophene; A: dicyano-indanone) but different halogen atoms and alkyl side chains. Due to the chlorination on the end-groups and the most and/or longest branched alkyl side chains on the backbone, the blended film composed of QCIC3 and donor poly{[2,6 '-4,8-di(5-ethylhexylthienyl)benzo [1,2-b : 4,5-b ']dithiophene]-alt-[5,5-(1 ',3 '-di-2-thienyl-5 ',7 '-bis(2-ethylhexyl)benzo[1 ',2 '-c : 4 ',5 '-c ']dithiophene-4,8-dione)]} (PBDB-T) exhibited the strongest pi-pi stacking and the most suitable phase-separation domains among the four blended films. Therefore, the QCIC3-based organic solar cells yielded the highest power conversion efficiency of 10.55 %. This work provides a pathway to optimize the molecular arrangements and enhance the photovoltaic property of simple electron acceptors through subtle chemical modifications.