Spontaneous solar water splitting with decoupling of light absorption and electrocatalysis using silicon back-buried junction.

Hui-Chun Fu, Purushothaman Varadhan, Chun-Ho Lin, Jr-Hau He

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Converting sunlight into a storable form of energy by spontaneous water splitting is of great interest but the difficulty in simultaneous management of optical, electrical, and catalytic properties has limited the efficiency of photoelectrochemical (PEC) devices. Herein, we implemented a decoupling scheme of light harvesting and electrocatalysis by employing a back-buried junction (BBJ) PEC cell design, which enables >95% front side light-harvesting, whereas the electrochemical reaction in conjunction with carrier separation/transport/collection occurs on the back side of the PEC cell. The resultant silicon BBJ-PEC half-cell produces a current density of 40.51 mA cm-2 for hydrogen evolution by minimizing optical, electrical, and catalytic losses (as low as 6.11, 1.76, and 1.67 mA cm-2, respectively). Monolithic fabrication also enables three BBJ-PEC cells to be connected in series as a single module, enabling unassisted solar water-splitting with a solar-to-hydrogen conversion efficiency of 15.62% and a hydrogen generation rate of 240 μg cm-2 h-1.
Original languageEnglish (US)
JournalNature communications
Volume11
Issue number1
DOIs
StatePublished - Aug 9 2020

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: J.H.H. greatly acknowledges the funding from King Abdullah University of Science and Technology (KAUST) and City University of Hong Kong.

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