Molecular design of triarylamine dyes incorporating phenylene spacer and the influence of alkoxy substituent on the performance of dye-sensitized solar cells

Molecular design and understanding the structure–property relationship of π-conjugated spacer play pivotal roles in realization of considerable enhancement performance of dye-sensitized solar cells (DSSCs). Three triphenylmaine dyes, namely MX11-13, have been designed and synthesized, which incorporate 2,2,6,6-tetramethylbenzo[1,2-d;4,5-d′]bis[1,3]dioxole (TMBD), phenyl and 1,4-dipropoxybenzene (DPB) as π-conjugated spacer, respectively. The effects of alkoxy substituent upon the photophysical, electro-chemical characteristics and performance of dye-sensitized solar cells are investigated. For a typical device, the MX13-based cell affords an overall power conversion efficiency (η) of 7.02%, with short-circuit photocurrent density (JSC), open-circuit voltage (VOC) and fill factor (ff) of 15.5 mA cm−2, 697 mV and 0.65, respectively.