A structural study of 1-phenyl-1,2,3,4-tetrahydroquinoline-based dyes for solid-state DSSC applications

D-π-A architecture metal-free organic dyes, with a tetrahydroquinoline unit as electron donor, were designed and synthesized for solid-state dye-sensitized solar cells. The sensitizer series was designed to develop a structure-property relationship. These dyes are obtained from relatively cheap starting materials, without the use of expensive catalysts, rigorously anhydrous or oxygen-free conditions. The highest solid-state device conversion efficiency (η) 3.3% (JSC = −5.9 mA cm−2, VOC = 780 mV) and fill factor FF = 0.72 under 100 mW cm−2 (AM 1.5G) solar irradiation was achieved with dye D4 employing a hydrazone fragment as the spacer between the donor 3-alkoxy-1-phenyl-1,2,3,4-tetrahydroquinoline and the rhodanine acceptor of the sensitizer.