Photo-Electrochemical Hydrogen Generation from Inverted Metamorphic Multijunction III-Vs

Our goal is to improve solar-to-hydrogen (STH) efficiency from just over 10% to over 20% via novel tandem semiconductor materials and configurations. Our primary focus is to develop inverted metamorphic multijunction (IMM) III-V semiconductors that have bandgaps optimized for water splitting. We will also discuss measurement challenges in appraising STH efficiency, some of which are specific to tandem absorbers. Using more stringent measurement standards, we have confirmed 16.2% STH on our most advanced IMM devices.