title: Understanding the synergistic effect of WO3-BiVO4 heterostructures by impedance spectroscopy.
abstract: WO3-BiVO4 n-n heterostructures have demonstrated remarkable performance in photoelectrochemical water splitting due to the synergistic effect between the individual components. Although the enhanced functional capabilities of this system have been widely reported, in-depth mechanistic studies explaining the carrier dynamics of this heterostructure are limited. The main goal is to provide rational design strategies for further optimization as well as to extend these strategies to different candidate systems for solar fuel production. In the present study, we perform systematic optoelectronic and photoelectrochemical characterization to understand the carrier dynamics of the system and develop a simple physical model to highlight the importance of the selective contacts to minimize bulk recombination in this heterostructure. Our results collectively indicate that while BiVO4 is responsible for the enhanced optical properties, WO3 controls the transport properties of the heterostructured WO3-BiVO4 system, leading to reduced bulk recombination.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Shi
authors.affiliation: Institute of Advanced Materials (INAM), Universitat Jaume I, 12071 Castelló, Spain. sjulia@uji.es.
authors.forename: Isaac
authors.initials: I
authors.lastname: Herraiz-Cardona
authors.affiliation: Institute of Advanced Materials (INAM), Universitat Jaume I, 12071 Castelló, Spain. sjulia@uji.es.
authors.forename: Luca
authors.initials: L
authors.lastname: Bertoluzzi
authors.affiliation: Departamento de Electrónica y Tecnología de Computadores, CITIC-UGR, Universidad de Granada, 18071 Granada, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Lopez-Varo
authors.affiliation: Institute of Advanced Materials (INAM), Universitat Jaume I, 12071 Castelló, Spain. sjulia@uji.es and Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Juan
authors.initials: J
authors.lastname: Bisquert
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea. lutts@yonsei.ac.kr.
authors.forename: Jong Hyeok
authors.initials: JH
authors.lastname: Park
authors.affiliation: Institute of Advanced Materials (INAM), Universitat Jaume I, 12071 Castelló, Spain. sjulia@uji.es.
authors.forename: Sixto
authors.initials: S
authors.lastname: Gimenez