Influence of Adsorption of para‐Aminothiophenol on Trap States and Recombination Kinetics at Plasmonic Ag‐TiO2 Heterostructure Interfaces

Abstract

AbstractThe variation of trap states and the involving kinetics on the Ag‐TiO2 interfaces after the adsorption of reactant molecules were explored with the help of the combination of spectroscopic, electrochemical and photoelectrochemical methods by using para‐aminothiophenol (PATP) as a probe molecule. The results of photoluminescence spectroscopy and chronoamperometry revealed the distribution of trap states of Ag‐TiO2 heterostructures and the influence of PATP's adsorption. Kinetic measurements of open‐circuit photovoltage showed that the adsorption of PATP affects not only the electron lifetime (τn) but also the recombination mechanism of charge‐carrier on Ag‐TiO2 heterostructures. The analysis of the obtained effective recombination orders indicated that the charge‐carrier recombination on the Ag‐TiO2 electrode followed second‐order kinetics, while the one of the Ag‐TiO2/PATP electrode evolved from first‐order kinetics at first (at higher Voc) to second‐order kinetics (at lower Voc).