Resistance-based analysis of limiting interfaces in multilayer water splitting photocathodes by impedance spectroscopy

Abstract

Electrochemical impedance spectroscopy is used to determine the potential-dependent resistances in multilayer photocathodes for water splitting. Limitations in the devices can thereby be identified and improvements proposed and investigated.

The role of ultra-thin MnOx co-catalysts on the photoelectrochemical properties of BiVO4 photoanodes

“…We apply a resistance-based analysis method on the resistances in the lms, as recently established by Moehl et al for multilayer water splitting photocathodes. 53 In order to assign the identity of each semicircle, the measurements were also conducted at different applied potentials. As shown in Fig.…”

Operandoelectrochemical study of charge carrier processes in water splitting photoanodes protected by atomic layer deposited TiO2

“…We note that even though several EC models have been developed to describe PEC processes, it is the capacitive rather than resistive elements which distinguish them. 23 This is why our following analysis is fully resistance-based. The tting details are presented in Fig.…”

“…Aerwards, the resistance increases again before it steeply drops as the overpotential of NiCat is overcome and oxygen evolution current sets in. 23,27 As the O 2 -involving photocurrent increases, the value of R ct drastically reduces and nally disappears at very positive potential region (aer 1.4 V RHE ), suggesting fast charge transfer kinetics at the catalyst/electrolyte interface. R TiO 2 , with an intermediate frequency range, is related to the charge carrier processes in the TiO 2 protective layer.…”

“…For a complex multilayer photoelectrode system with so far unknown equivalent circuit (EC), still the resistances of the different charge carrier processes can be extracted and their potential dependence studied. 22,23 The dual-working-electrode (DWE) technique is another powerful tool to study fundamental insights of water splitting photoelectrodes. While the rst working electrode (WE1) controls the potential at the back contact of the photoelectrode, the second working electrode (WE2) contacts either the catalyst on the surface or the photoabsorber surface itself, thereby enabling the in situ monitoring of, or control of, the surface potential.…”

Operando Analysis of Semiconductor Junctions in Multi-Layered Photocathodes for Solar Water Splitting by Impedance Spectroscopy

“…considering only the resistances from the EC model) can be used as a tool for identifying the limiting interfaces in Cu2O and Si-based multi-layered photocathodes. [12] Despite the simplicity and power of the resistance-based method, additional information obtainable from the EC elements, such as the capacitances and time constants, should be taken into account to fully exploit the advantages of the EIS method.…”