Efficiency and stability of narrow-gap semiconductor-based photoelectrodes

The conversion of solar energy into fuels is an attractive prospect for storing renewable energy, and photoelectrochemical technology represents a pathway by which solar fuels might be realized. Ideally, cost-effective photoelectrodes efficiently and stably drive anodic and/or cathodic half-reactions. However, no photoelectrode satisfies all the harsh requirements of practical applications, mainly involving high conversion efficiency and good stability. Narrow-gap semiconductor-based photoelectrodes have recently generated a great deal of interest because of their high conversion efficiency. The possible modification of the efficiency and stability using various structural engineering strategies has been largely responsible for the rapid growth of interest in these photoelectrodes. In this review, we aim to present the advances in the efficiency and stability of narrow-gap semiconductor-based photoelectrodes on three levels: fundamental bottlenecks, existing solution strategies, and applications.