Effects of electron acceptor groups on triphenylamine-based dyes for dye-sensitized solar cells: Theoretical investigation

Six novel D-π-A organic dyes based on 3D triphenylamine derivative (IDTTPA) featuring indenothiophene unit have been designed and theoretically investigated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). By modulating the anchoring group, the efficiency of D-π-A dyes-based dye-sensitized solar cells (DSSCs) can be further improved. Indeed, in this work, the effects of different acceptor groups in D-π-A dyes (A1-A6) before and after binding to TiO2 cluster on the electron injection to the surface ability were studied. The electronic structures, Density of States (DOS), Natural Bond Orbital (NBO) analysis, UV–vis spectra, and some key parameters associated with the short-circuit current density (Jsc) and the open-circuit photovoltage (Voc), such as light-harvesting efficiency (LHE), and electron injection driving force (ΔGinject), were computed to predict the most suitable dyes for DSSC application. Our calculations reveal that, compared with dye A1, dyes A4 and A6 improve the performance potentially due to their higher absorptivity as well as the strong adsorption stability of the corresponding acceptors.