Probing the material corrosion chemistry at the semiconductor/electrolyte interface for sustainable solar fuel generation

Abstract

Stability is one of the crit. aspects that greatly influence the future pathway of large-scale industrial application of integrated solar fuel generators. While a variety III-V semiconductors (GaAs, InP and GaP, etc.) with suitable band gaps can be employed in a tandem light-absorber device design, their material robustness under solar water-splitting conditions (pH=0 or pH=14) always remains a question. Thus, a fundamental and comprehensive understanding over the corrosion chem. of these technol.-important semiconductor materials is urgently required, which should be evaluated at exact conditions for hydrogen/oxygen evolution reactions. Herein, we systematically investigate this sophisticated material corrosion chem. in both strong acidic and basic electrolyte. Various techniques including inductively coupled plasma mass spectroscopy (ICP-MS), scanning electron microscope (SEM), XPS and at.-force microscopy (AFM) are all employed to reveal the phys. and chem. transformations occurring at the semiconductor/electrolyte interface. Combined with theor. considerations of thermodn. pourbaix diagrams, their diverse corrosion behaviors can be understood under varying conditions (under light/dark, with voltage bias/open-circuit, etc.). Eventually, rational strategies are designed to protect these semiconductors from rapid corrosion and achieve prolonged lifetime suitable for practical and sustained solar fuel generation.