Study of Donor-Acceptor-π-Acceptor Architecture Sensitizers with Benzothiazole Acceptor for Dye-Sensitized Solar Cells

Abstract

A new additional benzothiazole (BT) acceptor has been introduced into metal-free organic dyes (MCG1-MCG4) to construct donor-acceptor-π-acceptor (D-A-π-A) architecture with the systematic replacement of diheteroanthracene donors and heteroaromatic π-bridge components. BT not only facilitates effective electron transfer from the donor to the anchoring group, but also lowers the band gap. The planarity of the sensitizers induces J aggregation on TiO2, causes the redshift on TiO2, and enhances the light-harvesting efficiency up to λ=750-800nm. Transient absorption spectroscopy and electrochemical impedance spectroscopy have been used to understand the trends in short-circuit current (Jsc) and open-circuit voltage (Voc). Dye MCG4 showed a superior efficiency of 6.46%. DFT has been complemented with experimentally determined photoelectrochemical properties. These molecules are new and support π-bridge extension with BT for better performance of D-A-π-A organic sensitizers.