Theoretical study of the asymmetric organic dye with heteroleptic dual acceptors for dye-sensitized solar cells

Abstract

An asymmetric A-π-D-π-A’ organic dye (dye1) combining a red D − π−A dye (D35) and a blue D − π−A’ dye (DB) on each side of a triphenylamine (TPA) was designed, and a theoretical study was conducted to determine its utility as a dye-sensitized solar cell (DSSC). To gain insight into the factors responsible for the photovoltaic performance of the dye, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations for the dye were compared with those of reference dyes (D35 and DB). The absorption spectrum of the dyes differed due to different energy levels of the molecular orbitals (MOs) of each dye and intramolecular charge transfer (ICT). The results show that the heteroleptic di-anchoring dye1 had comparable photovoltaic properties to those of D35 and DB combined. As compared with the dyes containing single acceptors, the asymmetric organic dye containing heteroleptic dual acceptors showed competitive conversion efficiency of DSSCs, a broader absorption spectrum, and a higher molar extinction coefficient. These results indicate that dyes containing heteroleptic dual acceptors produces good photovoltaic properties for DSSCs.