Molecular Design and Computation of Dye Sensitizers with Multiple Electron Donor for DSSCs

Herein, indoline-based dye sensitizers with dual and triple electron donors (the TPA-In and the POZ-TPA-In dye) were designed and their electronic and optical properties were investigated theoretically to enhance photovoltaic performance as dye-sensitized solar cells (DSSCs). To gain insight into the factors responsible for photovoltaic efficiencies, we perform the density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations for these dyes. This study shows that all electron donor moieties might contribute to absorption process even for the dye with triple electron donor. From DFT and TDDFT calculations as well as frontier orbital analysis, this result is attainable when HOMO levels of the POZ-TPA-In dye were manipulated appropriately. It suggests that dye sensitizer with multiple electron donor could show better photovoltaic properties in case of proper design of its MO levels and consequently increase the conversion efficiency for DSSCs.