Engineering Perovskite Bandgap for Control of Hot-Electron Dynamics in Plasmonic Nanodiodes

Despite extensive research on utilizing plasmonic hot carriers to advance photovoltaics and photocatalysts, achieving high hot-carrier flux remains challenging due to their rapid relaxation. Recent studies have shown that combining plasmonic metals with perovskites improves hot-electron flow, due to the slow hot-electron relaxation in perovskites. Additionally, perovskites offer the advantage of facile bandgap tuning through composition changes. Herein, the influence of tuning the perovskite bandgap on the lifetime and flow of hot electrons in a perovskite/plasmonic Au/TiO₂ nanodiode is explored. The findings reveal that perovskites with wider bandgaps exhibit improved hot-electron lifetime and flow, attributed to the modified hot-electron energy favoring a slower energy loss rate, as verified by ultrafast transient absorption spectroscopic analysis. It is believed that the results successfully demonstrate the integration of engineered hot-carrier physics into device functions, providing valuable guidance for the design of optimized hot-carrier-based devices in the future.