Improved performance and stability of photoelectrochemical water-splitting Si system using a bifacial design to decouple light harvesting and electrocatalysis

Hui-Chun Fu, Purushothaman Varadhan, Meng Lin Tsai, Wenjie Li, Qi Ding, Chun-Ho Lin, Marcella Bonifazi, Andrea Fratalocchi, Song Jin, Jr-Hau He

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

Photoelectrochemical (PEC) splitting of water into hydrogen and oxygen is a promising way for the production of clean, and storable form of fuel but the PEC efficiency has remained low. Herein, we demonstrate enhanced light harvesting, charge carrier separation/transfer, and catalyst management with bifacial design for the Si-based photocathodes to achieve best-in-class hydrogen generation with excellent electrochemical stability. Decoupling the light harvesting side from the electrocatalytic surface nullifies parasitic light absorption and enables Si photocathodes that exhibit a photocurrent density of 39.01 mA/cm2 and stability over 370 h in 1 M H2SO4(aq) electrolyte due to fully covered a 15 nm Pt without any intentional protective layer. Furthermore, the bifacial Si photocathode system with semi-transparent Pt layer of 5 nm developed herein are capable of collecting sunlight not only on the light harvesting side but also on the back side of the device, resulting in a photocurrent density of 61.20 mA/cm2 under bifacial two-sun illumination, which yields 56.88% of excess hydrogen when compared to the monofacial PEC system. Combining the bifacial design with surface texturing and antireflection coating enables excellent omnidirectional light harvesting capability with a record hydrogen (photocurrent) generation, which provides a promising way to realize practical PEC water splitting applications.
Original languageEnglish (US)
Pages (from-to)104478
JournalNano Energy
Volume70
DOIs
StatePublished - Jan 13 2020

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: J.H.H. greatly acknowledges the baseline funding from King Abdullah University of Science and Technology (KAUST), KAUST Sensor Initiatives, KAUST Solar Center, and KAUST Catalysis Center. S.J. thanks the support from the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under award DE-FG02-09ER46664.

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