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

Abstract The variation of trap states and the involving kinetics on the Ag‐TiO 2 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‐TiO 2 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 ( τ n ) but also the recombination mechanism of charge‐carrier on Ag‐TiO 2 heterostructures. The analysis of the obtained effective recombination orders indicated that the charge‐carrier recombination on the Ag‐TiO 2 electrode followed second‐order kinetics, while the one of the Ag‐TiO 2 /PATP electrode evolved from first‐order kinetics at first (at higher V oc ) to second‐order kinetics (at lower V oc ).