Harnessing Hot Electrons in Core/Shell Quantum Dots for Photoelectrochemical Solar Energy Conversion

Colloidal InP/ZnSe(S) core/shell quantum dots (QDs) have exhibited exceptional optoelectronic performance in light-emitting applications, while their potential in solar energy conversion technologies is constrained by low carrier extraction efficiency. Although engineering the band structure or introducing localized states within the QD bandgap is effective to optimize charge extraction, the regulation of hot-electron dynamics within the bands has been largely neglected. In this work, we modulate the hot-electron dynamics in InP/ZnSeS QDs by incorporating Mn doping during the growth of the ZnSeS shell. Theoretical and experimental investigations both demonstrate that the introduction of Mn dopant enables efficient and directional transfer of hot electrons from InP core to ZnSeS shell before charge recombination, thus significantly improving the carrier extraction efficiency. As a result, the InP/ZnSeS:Mn QDs are utilized to fabricate solar-driven photoelectrochemical (PEC) devices, which deliver a maximum photocurrent density of 14.6 mA cm –2 under standard 1 sun illumination, representing a state-of-the-art performance among various QDs-based PEC systems.