Cu2O photocathodes with band-tail states assisted hole transport for standalone solar water splitting

Photoelectrochemical water splitting provides a promising solution for harvesting and storing solar energy. As the best-performing oxide photocathode, the Cu 2 O photocathode holds the performance rivaling that of many photovoltaic semiconductor-based photocathodes through continuous research and de...

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Bibliographic Details
Published in:Nature communications 2020-01, Vol.11 (1), p.318-318, Article 318
Main Authors: Pan, Linfeng, Liu, Yuhang, Yao, Liang, Dan Ren, Sivula, Kevin, Grätzel, Michael, Hagfeldt, Anders
Format: Article
Language:English
Subjects:
140/146
147/135
639/301/299/890
639/4077/909/4101/4050
639/4077/909/4101/4102
Copper oxides
Electromagnetic absorption
Energy harvesting
Holes (electron deficiencies)
Humanities and Social Sciences
multidisciplinary
Photocathodes
Photovoltaic cells
Photovoltaics
R&D
Recombination
Research & development
Science
Science (multidisciplinary)
Solar energy
Splitting
Thiocyanates
Transport
Water splitting
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Summary:Photoelectrochemical water splitting provides a promising solution for harvesting and storing solar energy. As the best-performing oxide photocathode, the Cu 2 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 2 O photocathode employs gold as the back contact which can lead to considerable electron-hole recombination. Here, we present a Cu 2 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 2 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. While solar-to-fuel conversion offers a promising technology to produce energy, device components can limit light absorption and reduce performances. Here, authors show copper thiocyanate to assist hole transport in photoelectrodes and enable a 4.55% solar-to-hydrogen efficiency in tandem devices.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-019-13987-5