Non-fullerene acceptors with thiazole π-bridge for organic solar cells

Intramolecular noncovalent conformational locks (NoCLs) have been found to be effective in increasing the rigidity and planarity of the molecular backbone. This, in turn, leads to reduced recombination energy and improved intramolecular charge transport mobility, resulting in significant enhancements in the photovoltaic performance of organic solar cell (OSC) devices. To take advantage of this effect, we designed and synthesized two small molecule non-fullerene acceptors (NFAs) with A-π-D-π-A structures using thiazole (Tz): IDTz-IC4F and IDTz-IC4Cl. With the synergistic assistance of NoCLs and halogenated end groups, the NFAs IDTz-IC4F and IDTz-IC4Cl exhibited power conversion efficiencies (PCEs) of 6.20 % and 6.06 %, respectively. This study presents a strategy for enhancing the PCE of OSCs by incorporating cooperative NoCLs and halogen end groups, providing an exciting avenue for designing high-performance non-fullerene materials in the future.