Title: Fused-Ring Nitrogen-rich Building Blocks to Design Non-fullerene Electron Acceptors for Organic Photovoltaics

Introduction: 

Organic solar cells are amongst the most promising renewable energy conversion solutions due to their low-cost and flexibility. Fused-ring non-fullerene electron acceptors (FREAs) having well-connected π-conjugated framework enables higher electron charge transfer and electron mobilities, which has frequently exhibited champion PCE.1-3 Herein, we introduce new multi-directional FREAs containing a Benzotrithienopyrrole central core connected to a π-bridge acceptor, either benzo[c][1,2,5] thiadiazole or benzo[d][1,2,3]triazole, and one of three terminal acceptors: 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile, malononitrile, or 2-(3-methyl-4-oxothiazolidin-2-ylidene)malononitrile as FREAs for organic electronics.