Substantially enhanced front illumination photocurrent in porous SnO2 nanorods/networked BiVO4 heterojunction photoanodes

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 6; no. 30; pp. 14633 - 14643
• Main Authors: Bhat, Swetha S M, Suh, Jun Min, Choi, Seokhoon, Seung-Pyo, Hong, Lee, Sol A, Kim, Changyeon, Cheon Woo Moon, Mi Gyoung Lee, Jang, Ho Won
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2018
• Subjects: Bismuth oxides; Charge efficiency; Charge transfer; Charge transport; Configuration management; Current efficiency; Heterojunctions; Illumination; Nanorods; Photoanodes; Photoelectric effect; Photoelectric emission; Tandem configuration; Tin dioxide; Vanadates
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c8ta03858a

BiVO4 is a promising photoanode for photoelectrochemical applications owing to its suitable band edge position for oxygen evolving reactions. High photocurrent under front illumination is very much essential to design tandem structures with a wireless configuration. However, the performance of BiVO4 under front illumination is limited due to poor charge transport properties. Here, we show that network-like BiVO4 coupled with porous SnO2 nanorods (NRs) is a promising model to enhance the front illumination performance. A very high photocurrent density of 5.6 mA cm−2 and 5.5 mA cm−2 has been obtained from the front and back illumination at 1.23 V vs. the reversible hydrogen electrode, respectively. We demonstrate that the appropriate nanostructuring of SnO2 NRs/BiVO4 is the underlying technology to tune the performance under directional illumination. The SnO2 NRs/BiVO4 exhibits a maximum incident photon to current efficiency of ∼80% under front and back illumination. A systematic study reveals that the optimized network like BiVO4 coated on porous SnO2 NRs synergistically boosts both the charge separation and transfer efficiencies of the photoanode resulting in a significantly high photocurrent for illumination on either side. This work provides a direction to achieve enhanced photocurrent during front and back side illumination in order to realize a wireless tandem configuration.