Dye regeneration mechanisms of dye sensitized solar cells: Quantum chemical studies on the interaction between iodide and O/S-containing organic dyes

• two homologous organic dyes are calculated to reveal the regeneration mechanism.
• three kinds of dye regeneration reaction processes by iodide have been investigated.
• dye+ and I2- is the most favorite regeneration mechanism.
• theoretically prove that S-substitution in donor unit further decreases ΔG barrier.

In order to explore the mechanism of dye regeneration, three possible kinds of dye regeneration reaction processes for two homologous organic dyes by iodide have been investigated theoretically. The objective of this study is to interpret the significantly different regeneration rate constant between the organic dyes in the change from oxygen to sulfur in two triphenylamine donor unit. The corresponding surface electrostatic potential, the interaction energy and the Gibbs free energy differences in every reaction steps are calculated to reveal the different effect between iodide and O/S-containing organic dyes. The data indicate that the direct reaction between dye+ and I2- is the most favorite regeneration mechanism. Furthermore, the S-substitution in donor unit further decreases Gibbs free energy differences barrier and positively impacts the regeneration rate.

The different effect between iodide and O/S-containing homologous organic dyes are calculated to reveal that the direct reaction between dye+ and I2- is the most favorite regeneration mechanism. Furthermore, the S-substitution in donor unit further decreases ΔG barrier and positively impact the regeneration rate.Figure optionsDownload as PowerPoint slide