The effect of different pi-bridge configuration on bi-anchored triphenylamine and phenyl modified triphenylamine based dyes for dye sensitized solar cell (DSSC) application: A theoretical approach

Twenty eight bi-anchored triphenylamine (TH-1 to TH-14) and phenyl modified triphenylamine (PH-TH-1 to PH-TH-14) based metal free organic dyes are designed for DSSC application. The electronic effect of different err-bridge configurations in donor-pi-bridge-acceptor (D-pi-A)(2) structure was theoretically simulated and verified using density functional theory (DFT) and time dependent density functional theory (TD-DFT). The triphenylamine and phenyl modified triphenylamine groups are used as donor and cyanoacrylic acid group is used as acceptor. Thiophene and cyanovinyl groups are used as pi-bridge. The ground state molecular structure was optimized by density functional theory and the electronic absorption spectra were calculated by time dependent density functional theory. The light harvesting efficiency (LHE), dye regeneration energy (Delta(Greg)) and electron injection energy (Delta G(inject)) are determined by computational examination. It is observed that, when the number of pi-bridge increases, the band gap of the dye decreases. Also the absorption maximum and molar extinction coefficient of the dyes are increased. Theoretical result shows that the thiophene-cyanovinyl and thiophene-thiophene-cyanovinyl-cyanovinyl configurations give broader and red shifted absorption spectrum compared to other configurations. Also the results of phenyl modified triphenylamine (PH-TH) dyes clearly show better absorption and dye regeneration energy compared to TH dyes. (C) 2017 Elsevier Inc. All rights reserved.