Journal
ENERGY & ENVIRONMENTAL SCIENCE
Volume 10, Issue 2, Pages 570-579Publisher
ROYAL SOC CHEMISTRY
DOI: 10.1039/c6ee03505a
Keywords
-
Funding
- DOE Basic Energy Sciences [DE-SC0014279]
- Sloan Fellowship
- NSF GRFP [1309047]
- government of India Department of Science and Technology
- Indo-U.S. Science and Technology Forum (IUSSTF)
- U.S. Department of Energy (DOE) [DE-SC0014279] Funding Source: U.S. Department of Energy (DOE)
Ask authors/readers for more resources
Si is a desirable photoanode material for use in photoelectrochemical water-splitting devices. However, Si self-passivates during the oxygen evolution half reaction and requires a protection layer to maintain high photoanodic efficiency. Thin evaporated metallic Ni layers have been reported to protect Si while also enhancing the kinetics for oxygen evolution. Maximizing performance of these and related protected/ catalyzed semiconductors requires a fundamental understanding of the semiconductor|catalyst|solution interface. We use dual-working-electrode (DWE) photoelectrochemistry measurements to directly measure the interface's electronic properties in situ during operation. By controlling the Ni thickness (3, 5, and 20 nm), we confirm that favorable shifts in photocurrent onset are correlated with thinner protection layers. Photoelectrochemical DWE measurements are used to test various prevailing hypotheses for the origin of this behavior. We find evidence that increased photovoltage is due to the development of a spatially inhomogeneous buried junction wherein high barrier regions arise via adventitious SiO2 growth. Thinner protection layers more readily promote this behavior by facilitating solution permeation to the n-Si| Ni interface. Repeated electrochemical cycling of thicker catalyst layers can achieve similar behavior and improve the photocurrent onset by as much as 300 mV. The results are discussed in the context of the general design principles for metal-insulator-semiconductor protected photoanodes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available