Defect Engineering of Ternary Cu–In–Se Quantum Dots for Boosting Photoelectrochemical Hydrogen Generation

Abstract

Cu-In-Se quantum dot are promising materials for solar fuel generation due to tunable band gap, high absorption coefficiecnt, low toxicity. Although defects significantly affect the photoelectrochemical performacne and photophysical properties of quantum dot, the effects of defects have not studied sufficiently yet. Herein, we developed the defect engineering of Cu-In-Se quantum dot for highly efficient solar fuel conversion. Lewis acid and base reaction between oleyammonium selenocarbamate and metal halide-oleyamine complexs are modulated to realize Cu-In-Se quantum dot with the tunable amount of Cu vacancies without changing their morphology. Among them, CISe QD with In/Cu = 1.55 ratio exhibited the most excellent photoelectrochemical hydrogen production with outstanding photocurrent density up to 10.7 mA cm-2 (at 0.6 VRHE), caused by enhanced carrier concentration & lifetimes of the quantum dot and suitable electronic and band structure. The suggestion which can efficiently control the defects in heavy-metal free ternary quantum dot, provides the detail understanding of the effects of defects and offers a practical approach to improve photoelectrochemical hydrogen evolution.