Cu<sub>2</sub>O photocathodes with band-tail states assisted hole transport for standalone solar water splitting.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31949135.
- Also identified by DOI 10.1038/s41467-019-13987-5 and PMC identifier 6965123.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Photoelectrochemical water splitting provides a promising solution for harvesting and storing solar energy. As the best-performing oxide photocathode, the Cu<sub>2</sub>O photocathode holds the performance rivaling that of many photovoltaic semiconductor-based photocathodes through continuous research and development. However, the state-of-the-art Cu<sub>2</sub>O photocathode employs gold as the back contact which can lead to considerable electron-hole recombination. Here, we present a Cu<sub>2</sub>O photocathode with overall improved performance, enabled by using solution-processed CuSCN as hole transport material. Two types of CuSCN with different structures are synthesized and carefully compared. Furthermore, detailed characterizations reveal that hole transport between Cu<sub>2</sub>O and CuSCN is assisted by band-tail states. Owing to the multiple advantages of applying CuSCN as the hole transport layer, a standalone solar water splitting tandem cell is built, delivering a solar-to-hydrogen efficiency of 4.55%. Finally, approaches towards more efficient dual-absorber tandems are discussed.