Fluorinated heptacyclic carbazole-based ladder-type acceptors with aliphatic side chains for efficient fullerene-free organic solar cells

摘要: Molecular engineering of non-fullerene acceptors (NFAs) is a promising strategy to uncover new structure–property relationships and design principles for developing next-generation high performance n-type materials. Two dithienocyclopentacarbazole (DTC)-based NFAs, DTC(4R)-IC DTC(4R)-4FIC, are synthesized elucidate the effects incorporating aliphatic side chains 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) end groups on thermal optoelectronic properties these NFAs. An inverted organic solar cell architecture ITO/ZnO/J71:NFA/MoO3/Ag employed. By replacing phenyl-based with carbon bridges carbazole-based core, device containing exhibits an enhanced PCE 9.61%, VOC 0.94 V, JSC 16.44 mA cm−2, FF 62.00%, whereas DTC(4Ph)-IC 7.76%. The incorporation 2FIC affords DTC(4R)-4FIC featuring better relative DTC(4R)-IC, more red-shifted absorption edge, broader range upon fluorination. Notably, fabricated Voc 0.82 Jsc 18.92 70.22% highest 10.89%, which by far NFA heptacyclic carbazole cores.