Fused Benzotriazole A-Unit Constructs a D-π-A Polymer Donor for Efficient Organic Photovoltaics.

Herein, we originally developed a fused ring building block as an acceptor unit, namely, 2,6,10-trihydro-carbazole[3,4- c :5,6- c ]bis[1,2,5]-triazole (CTA), through fusing two benzotriazoles (BTA) with a pyrrole ring. A p-type polymer PE93 containing the CTA unit exhibits relatively high molecular energy levels and excellent luminescent properties. The PE93:BTA76-based solar cell obtained a device efficiency of 12.16%, with a V OC of 0.94 V and a low nonradiative recombination loss of 0.18 eV. The results suggest that the CTA unit is an efficient acceptor unit to achieve excellent photovoltaic performance.