Enhanced Hydrogen Evolution under Simulated Sunlight from Neutral Electrolytes on (ZnSe) 0.85 (CuIn 0.7 Ga 0.3 Se 2 ) 0.15 Photocathodes Prepared by a Bilayer Method.

A (ZnSe) _0.85 (CuIn _0.7 Ga _0.3 Se ₂ ) _0.15 photocathode with a bilayer structure was fabricated and found to exhibit a photocurrent almost twice that of a photocathode with a monolayer structure during hydrogen evolution from water. The cathodic photocurrent reached maximum values of 12 and 4.9 mA cm ^-2 at 0 and 0.6 V _RHE in a neutral phosphate buffer under simulated sunlight, while the half-cell solar-to-hydrogen conversion efficiency was 3.0 % at 0.6 V _RHE , with a maximum value of 3.6 % at 0.45 V _RHE . Cross-sectional mapping of the electron-beam-induced current established that the increased photocurrent can be attributed to improved uniformity at the solid-liquid junction in the bilayer sample, which results in enhanced carrier collection.
(© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)