Exploring N3 ruthenium dye adsorption onto ZnTiO3 (101) and (110) surfaces for dye sensitized solar cell applications: Full computational study

Abstract

TiO2 and ZnO binary oxide films are extensively investigated as photo-anodes in dye-sensitized solar cells (DSSCs), due to their large surface area, high electron mobility and chemical stability features. ZnTiO3 perovskite is investigated as a photoanode, with N3 ruthenium dye, to design a new DSSC. First principal calculations based on DFT methods have been carried out to study the adsorption process of the ruthenium dye onto ZnTiO3 (101) and (110) surfaces. The energy levels of N3 dye are studied and compared to available experimental data. The calculated energy band gap for ZnTiO3 is 3.10 eV, which is in good agreement with experimental data (3.18 eV). The N3 dye is chemisorbed on the perovskite surface, via its carboxylic groups (COOH) which link to the (101) surface and two monodentate (ME) ester modes in (110) with bidentate bridging (BB) adsorption mode. The calculated adsorption energy (−241.50 kcal/mol) for the resulting N3@ZnTiO3 complex, is much higher than the values for N3@ZnO (−89.58 kcal/mol) and N3@TiO2 (−146.90 kcal/mol). The high adsorption energy of N3 dye, onto the perovskite surfaces, shows the potential value to use perovskites in future DSSCs.