Amorphous Si Thin Film Based Photocathodes with High Photovoltage for Efficient Hydrogen Production
By Lin, Yongjing; Battaglia, Corsin; Boccard, Mathieu; Hettick, Mark; Yu, Zhibin; Ballif, Christophe; Ager, Joel W. & Javey, Ali
Published in Nano Letters
2013
Abstract
An amorphous Si thin film with TiO2 encapsulation layer is demonstrated as a highly promising and stable photocathode for solar hydrogen production. With platinum as prototypical cocatalyst, a photocurrent onset potential of 0.93 V vs RHE and saturation photocurrent of 11.6 mA/cm2 are measured. Importantly, the a-Si photocathodes exhibit impressive photocurrent of ∼6.1 mA/cm2 at a large positive bias of 0.8 V vs RHE, which is the highest for all reported photocathodes at such positive potential. Ni -Mo alloy is demonstrated as an alternative low-cost catalyst with onset potential and saturation current similar to those obtained with platinum. This low-cost photocathode with high photovoltage and current is a highly promising photocathode for solar hydrogen production.