Enhanced Hydrogen Evolution under Simulated Sunlight from Neutral Electrolytes on (ZnSe)0.85 (CuIn0.7 Ga0.3 Se2 )0.15 Photocathodes Prepared by a Bilayer Method.

A (ZnSe)0.85 (CuIn0.7 Ga0.3 Se2 )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 VRHE in a neutral phosphate buffer under simulated sunlight, while the half-cell solar-to-hydrogen conversion efficiency was 3.0 % at 0.6 VRHE , with a maximum value of 3.6 % at 0.45 VRHE . 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.