Alloy-Inserted P-N Junction as Photocathode for Solar Hydrogen Application
林佑錩1,2*, 陳三元1, 林彥谷2
1Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
2Science Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
* presenting author:Yu-Chang Lin,
The Cu2O-based photocathode is considered as one of the most promising photocathodes for high performance water splitting under sunlight. However, the relatively negative onset potential for H2 production of these photocathode impedes further optimization of the solar-to-fuel conversion efficiency. Here, we have prepared a sandwich structure via using Au-Ag alloy inserted between p- Cu2O and n-Cu2O. The p-Cu2O/alloy/n-Cu2O electrode achieves a high photocurrent of 1.6 mA/cm2 at 0.7 V vs. RHE and a positive onset potential of 0.74 V vs. RHE (under AM 1.5 global illumination). The overall photoelectrochemical performance of the p-Cu2O/alloy/n-Cu2O photocathode might be derived from the well-established solid-state Z-scheme. Importantly, alloy possibly acts as an electron mediator for the transfer of electrons from the CB of p-Cu2O to the VB of n-Cu2O.

Keywords: Solar hydrogen, Sandwich structure, Photocathode, Photoelectrochemical, Cuprous Oxide