Substituent effects in a double rhodanine indoline dye on performance of zinc oxide dye-sensitized solar cell

The solar-light-to-electricity conversion efficiency of substituted indoline dyes depended on short-circuit photocurrent density which is affected by maximum incident photon-to-current efficiency. The oxidation potential of the double rhodanine indoline dyes needed to be >∼0.2 V vs Fc/Fc+ in acetonitrile to show high incident photon-to-current efficiency in a zinc oxide, dye-sensitized solar cell. To make a molecular design of highly efficient indoline dyes, the HOMO energy level should be more negative than ∼−4.9 eV by the DFT calculations.