Solution-processable star-shaped photovoltaic organic molecule with triphenylamine core and thieno[3,2-b]thiophene–dicyanovinyl arms

Abstract

A new solution-processable star-shaped D–π–A molecule with triphenylamine (TPA) as core and donor unit, dicyanovinyl (DCN) as end group and acceptor unit, and 3,6-dihexyl-thieno[3,2-b]thiophene (DHT) as π bridge, S(TPA–DHT–DCN) was synthesized for the application as donor material in solution-processed bulk-heterojunction organic solar cells (OSCs). The compound exhibits broad absorption in the visible region with suitable energy levels, which are desirable for application as a donor material in organic solar cells. The OSC devices based on S(TPA–DHT–DCN) as the donor and PC71BM as the acceptor (1:2, w/w) exhibited power conversion efficiency (PCE) of 2.87%, with high open circuit voltage (Voc) of 0.96V, short circuit current density (Jsc) of 6.80mA/cm2, and fill factor (FF) of 43.5%, under the illumination of AM.1.5, 100mW/cm2. The Voc of 0.96V for S(TPA–DHT–DCN) is among the top values for the solution-processed molecular-based OSCs reported so far.