Effect of the Si/TiO2/BiVO4 heterojunction on the onset potential of photocurrents for solar water oxidation

Hyejin Jung; Sang Youn Chae; Changhwan Shin; Byoung Koun Min; Oh-Shim Joo; Yun Jeong Hwang

doi:10.1021/am5086484

Effect of the Si/TiO2/BiVO4 heterojunction on the onset potential of photocurrents for solar water oxidation

ACS Appl Mater Interfaces. 2015 Mar 18;7(10):5788-96. doi: 10.1021/am5086484. Epub 2015 Mar 9.

Authors

Hyejin Jung^{1

2}, Sang Youn Chae^{1

3}, Changhwan Shin⁴, Byoung Koun Min^{1

2}, Oh-Shim Joo¹, Yun Jeong Hwang^{1

2}

Affiliations

¹ †Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
² ‡Korea University of Science and Technology, Daejeon 305-350, Republic of Korea.
³ §Department of Chemistry, College of Science, Korea University, Seoul 136-713, Republic of Korea.
⁴ ∥School of Electrical and Computer Engineering, University of Seoul, Seoul 130-743, Republic of Korea.

PMID: 25720751
DOI: 10.1021/am5086484

Abstract

BiVO4 has been formed into heterojunctions with other metal oxide semiconductors to increase the efficiency for solar water oxidation. Here, we suggest that heterojunction photoanodes of Si and BiVO4 can also increase the efficiency of charge separation and reduce the onset potential of the photocurrent by utilizing the high conduction band edge potential of Si in a dual-absorber system. We found that a thin TiO2 interlayer is required in this structure to realize the suggested photocurrent density enhancement and shifts in onset potential. Si/TiO2/BiVO4 photoanodes showed 1.0 mA/cm(2) at 1.23 V versus the reversible hydrogen electrode (RHE) with 0.11 V (vs RHE) of onset potential, which were a 3.3-fold photocurrent density enhancement and a negative shift in onset potential of 300 mV compared to the performance of FTO/BiVO4 photoanodes.

Keywords: BiVO4; Si; TiO2; dual absorber; heterojunction; onset potential.

Publication types

Research Support, Non-U.S. Gov't