Predicting photovoltaic parameters using DFT and TD-DFT calculations of novel triphenylamine-based organic dyes: The effect of the internal or auxiliary acceptors on photovoltaic performance for DSSC

Abstract

The power conversion efficiency (PCE) of a series of novel D-Ai-π-A and D-π-Aa-A type triphenylamine-based organic dyes with different internal or auxiliary acceptors, respectively, is predicted using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The geometrical configurations of the isolated and adsorbed dyes on the TiO2 surface are optimized. The key electronic parameters that can influence the PCE of DSSCs like light harvesting efficiency (LHE), electron injection energy ΔGinj, dye regeneration energy ΔGreg, reorganization energy (λ), dipole moment (μ), the shift of the conduction band edge ΔECB after adsorption on TiO2 surface, the chemical, and the ICT parameters are determined and investigated. The predicted PCE of 7.88 % agrees well with the experimental 7.3 %, confirming that our methodology is valid and credible. Indeed, the predicted PCE of the designed dyes are all higher than the reference dye and up above 13 % for three of them, indicating that this study can provide new clues for the experimental synthesis of highly efficient metal-free organic sensitizers for DSSCs.