Asymmetric chlorination of A2-A1-D-A1-A2 type non-fullerene acceptors for high-voltage organic photovoltaics

Herein, we synthesized an asymmetric A(2)-A(1)-D-A(1)-A(2) type small molecule nonfullerene acceptor (NFA), HCl-BTA3, by chlorination on one side of A(1). The synergistic effect of the asymmetric structure and chlorination endows HCl-BTA3 with a large dipole moment, close molecular packing, and high-efficiency charge transfer and transport. After being blended with a carboxylate-based polymer donor, TTC-Cl, HCl-BTA3 achieved a high open-circuit voltage (V-OC) of 1.20 V and a satisfactory power conversion efficiency (PCE) of 11.2%, which are among the highest values for high-voltage carboxylate-based polymers.

Automated summary

In this study, an asymmetric small molecule nonfullerene acceptor was synthesized through chlorination on one side, resulting in a large dipole moment, close molecular packing, and high-efficiency charge transfer and transport. When blended with a carboxylate-based polymer donor, the acceptor achieved a high open-circuit voltage and a satisfactory power conversion efficiency, reaching some of the highest values for carboxylate-based polymers.