Different anchoring ligands for Ru complexes dyes and the effect on the performance of ZnO-based Dye-Sensitized Solar Cell (DSSC): A computational study

Abstract

Chemical modifications allow to design new sensitizers for Dye-Sensitized Solar Cells (DSSC). This investigation aims to analyze new Ru complexes-based sensitizers for ZnO-based DSSC by substituting carboxylic acid groups with phendione (PHEN) and acetylacetone (ACAC) anchoring ligands while using isothiocyanate (NCS) and cyanide (CN) as ancillary ligands. The electronic structure of these complexes and their charge transport mechanism were analyzed using Time-Dependent Density Functional Theory (TD-DFT). The obtained results show that PHEN is a good substituent in these complexes since the obtained HOMO-LUMO gaps are close to 1.9 eV. Additionally, based on the donor–acceptor properties, Ru-PHEN complexes are better electron acceptor groups, whereas Ru-ACAC present better electron donor properties for electronic transporting processes with ZnO and the electrolyte. This theoretical study is a practical guide to the molecular engineering of alternative dyes used in ZnO-based DSSC.