Synthesis of bianchored metal free organic dyes for dye sensitized solar cells

Two bianchored metal free organic dyes (Car-th-CN and Dpa-th-CN) were designed and synthesized for DSSC application, in which carbazole or diphenylamine moieties were used as the donor, cyano vinyl thiophene unit as the pi-bridge and cyanoacrylic acid group as the electron acceptor. The structures of the synthesized dyes were confirmed by NMR, HR-Mass and elemental analysis. The optical, electrochemical, theoretical and photovoltaic properties of the synthesized dyes were investigated. Fabricated photovoltaic devices based on carbazole unit as a donor (Car-th-CN) showed a maximum current conversion efficiency of 4.04% under AM 1.5 illumination (85 mW cm(-2)) and monochromatic incident photon to current efficiency (IPCE) of 38.1%. The reason for the higher efficiency of Car-th-CN is due to the planar nature of carbazole moiety and hence increases the capability of adsorbed dye amount and electron lifetime in TiO2 surface. (c) 2013 Elsevier Ltd. All rights reserved.