Seneca Talk by Prof. David J. Fermín
SENECA Talks is a monthly seminar series on Solar ENErgy Conversion and StorAge organised by EnergyVille/imec/UHasselt (imo-imomec).
The upcoming Seneca Talk will be given by Prof. David J. Fermín (Bristol Electrochemistry and Solar Team, School of Chemistry, University of Bristol, UK).
Dynamic Photoelectrochemical Responses at the Semiconductor/Electrolyte Interface: Where to Start?
Dynamic photoelectrochemical techniques such as photocurrent transients, intensity modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) and photoelectrochemical impedance spectroscopy (PEIS) can provide accurate kinetic and mechanistic information about processes taking place at the semiconductor/electrolyte interface. Over the last decades, the implementation of these techniques has become more widespread due to their incorporation into commercial instruments. In the case of single crystal semiconductor electrodes, such as those underpinning the seminal works by Gerischer and Lewerenz, models have been developed to rationalize dynamic photoelectrochemical measurements assuming high carrier mobilities and well-defined potential distribution across the interface. However, the same models are often invoked in complex nanostructured interfaces, as well as multi-electron transfer reactions, in which the underlying basic assumptions often breakdown. In this contribution, Prof. Fermín will discuss key fundamental concepts associated with the analysis of:
1. IMPS and PEIS of multi-electron transfer reactions
2. Photocurrent transient measurements as a function of potential bias and photon-flux at complex interfaces
Through a set of examples, he will contrast responses at ‘model’ semiconductor surfaces 1,2 with those in texture binary and ternary metal-oxide semiconductors. 3-7 These examples illustrate the type of simple time-resolved experiments which ought to be conducted in order to develop a self-consistent analysis of IMPS and PEIS data.
1- D.J. Fermin et al. J. Electroanal. Chem. 473 (1999) 192
2- D. Tiwari and D.J. Fermin. Electrochim. Acta 254 (2017) 223
3- Q. Zhang et al. J. Phys. Chem. C 118 (2014) 1820
4- X. Sun et al. Appl. Mater. Interfaces 12 (2020) 31486
5- X. Sun et al. Adv. Energy Mater.10 (2020) 2002784
6- X. Sun et al. Chem. Sci. 13 (2022) 11252
7- Gonzalez-Poggini et al. ACS Appl. Energy Mater. 7, (2024) 2622
About the speaker
After completing his undergraduate degree at Universidad Simón Bolívar, Venezuela, with a final year project “Electrochemical Generation and Growth of Pyrrole” and spending a year as a research assistant, David Fermín joined Professor Laurence Peter’s group at the University of Bath where he gained his PhD with a thesis entitled “Semiconductor Photoelectrochemistry: Multi-electron Transfer Processes at Illuminated Semiconductor | Electrolyte Interfaces” .
David moved to Switzerland to become a postdoctoctoral fellow at École Polytechnique Fédérale de Lausanne (EPFL). David spent six years at EPFL before moving to Universität Bern in 2003. After 4 years in Bern, David and his group relocated to the University of Bristol, England, and the Bristol Electrochemistry group was created.
With the award of a professorship in 2013, David has continued to develop the group and establish firm links with electrochemistry groups around the world.
