Plasmon resonance energy transfer and hot electron injection induced high photocurrent density in liquid junction Ag@Ag2S sensitized solar cells

Abstract

An in situ technique was developed to deposit Ag@Ag₂S core–shell quantum dots on a SnO₂ mesoporous film for solar energy conversion. When adopted as a photoanode, an impressive high photocurrent density of ∼25.6 mA cm⁻² was demonstrated in a cell configuration using polysulfide S²⁻/S_n²⁻ as an electrolyte and Cu₂S/brass as a counter electrode, which leads to a power conversion efficiency of ∼0.784% for this environmentally benign device. Optical measurements showed that Ag nanoparticles could be employed as plasmon resonance centers to enhance the harvesting efficiency of incident light at the visible and near-infrared range. Moreover, photoluminescence spectra demonstrated fast charge transfer at Ag@Ag₂S/SnO₂ interfaces, which facilitates direct hot electron injection from sensitizers to the SnO₂ matrix and finally gives rise to the high photocurrent density.