Effect of Different Site Trifluoromethylbenzoic Acid Organic Photosensitizer for Dye‐sensitized Solar Cells

Abstract

AbstractTwo novel D‐A‐π‐A triazatruxene (TAT)‐based photosensitizers with different acceptor, namely SL201 and SL202, respectively, have been successfully synthesized and applied in dye‐sensitized solar cells (DSSCs). The trifluoromethyl as strong electron‐withdrawing group was introduced to different sites of benzoic acid, in order to enhance the electron‐withdrawing ability of the acceptor, broaden the light capture ability and improve power conversion efficiency (PCE) of the DSSCs. Due to the steric hindrance effect, the molecular planarity of the trifluoromethyl group at different positions in the molecule is different, which leads to different photovoltaic performance of DSSCs. Finally, the DSSCs based on SL202 obtain a higher PCE of 9.8 %, short‐circuit current density (Jsc) of 15.3 mA/cm2, an open‐circuit voltage (Voc) of 927 mV and a fill factor (FF) of 0.69, compared with 9.0 % of SL201, using Co2+/Co3+ complex redox couple under standard AM 1.5G solar irradiation (100 mW/cm2). The same chemical group at different positions will produce different molecular planarity, further causing different photovoltaic performance of devices.