Role of Copper Doping in Heavy Metal-Free InP/ZnSe Core/Shell Quantum Dots for Highly Efficient and Stable Photoelectrochemical Cell

As emerging eco-friendly alternatives to traditional Cd/Pb-based quantum dots (QDs), InP/ZnSe(S) core/shell QDs have demonstrated huge potential in light-emitting technologies. So far, these QDs have been rarely employed in solar energy conversion applications due to their type-I band structure offering limited photo-induced charge carrier separation and transfer. Here, a controllable Cu shell doping approach is reported to engineer the optoelectronic properties of InP/ZnSe core/shell QDs and realize high performance and stable solar-driven photoelectrochemical (PEC) hydrogen evolution. As compared to the pristine InP/ZnSe QDs, the Cu-doped core/shell QDs exhibit enhances the photo-induced electron transfer rate due to the capture of photo-generated holes via Cu impurity states in the shell, leading to improved photocurrent density and long-term durability in as-fabricated InP/ZnSe:Cu QDs-PEC devices under standard one sun illumination. The results indicate that the doping of Cu in the shell has a preeminent effect on the optoelectronic properties of the core/shell QDs and may open up new avenues to tailor eco-friendly core/shell QDs for high performance and stable solar energy conversion.