Determining cost-effective semiconductors exhibiting desirable properties for commercial photoelectrochemical water splitting remains a challenge. Herein, we report a Sb2Se3 semiconductor that satisfies most requirements for an ideal high-performance photoelectrode, including a small band gap and favourable cost, optoelectronic properties, processability, and photocorrosion stability. Strong anisotropy, a major issue for Sb2Se3, is resolved by suppressing growth kinetics via close space sublimation to obtain high-quality compact thin films with favourable crystallographic orientation. The Sb2Se3 photocathode exhibits a high photocurrent density of almost 30 mA cm−2 at 0 V against the reversible hydrogen electrode, the highest value so far. We demonstrate unassisted solar overall water splitting by combining the optimised Sb2Se3 photocathode with a BiVO4 photoanode, achieving a solar-to-hydrogen efficiency of 1.5% with stability over 10 h under simulated 1 sun conditions employing a broad range of solar fluxes. Low-cost Sb2Se3 can thus be an attractive breakthrough material for commercial solar fuel production.
Bibliographical noteFunding Information:
This work was supported by a National Research Foundation (NRF) of Korea grant (No. 2012R1A3A2026417); a Creative Materials Discovery Program (NRF-2018M3D1A1058793) funded by the Ministry of Science and ICT; the Korea Center for Artificial Photosynthesis (KCAP, No. 2009–0093880), funded by the MSIT; Project No. 10050509 funded by the MOTIE of Republic of Korea; and the UK EPSRC project number EP/N014057/1.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)