Sustainable Power Webinar Series
Charge carrier dynamics as a guide to materials design for solar fuel production
Abstract
Solar energy conversion and storage in fuels and chemicals holds the potential to transform our largest CO2-emitters such as the transport and electricity sectors and the chemical industry. There are two approaches currently intensively studied i) direct conversion via photocatalysis and ii) photo-driven electrocatalysis. For the water splitting reaction, it has been modelled that both pathways could in principle achieve solar-to-hydrogen efficiencies of ~30%. In practice however, photocatalytic or photoelectrochemical systems have shown efficiencies of ≤10% and more commonly around 1%. In this talk, I will compare both approaches from the viewpoint of charge carrier recombination and extraction kinetics in the photoabsorber that converts solar energy to electricity in solar cells versus directly to a fuel like hydrogen in solar-to-fuel devices. I will highlight recent studies on polycrystalline thin film Cu(In,Ga)Se2 solar cells and novel as well as well-studied oxide photocatalysts such as La,Rh:SrTiO3 and hematite. These studies give interesting insights into material design of novel photocatalysts using band gap engineering strategies while also pointing towards some intrinsic material properties that might be difficult to re-engineer (such as the nature and extend of polaron formation) and require more understanding between the electronic structure of a material and its semiconducting properties.
Biography
Dr Ludmilla Steier is Imperial College Research Fellow in the Department of Materials where she is forming the Atomic-scale Material Design Lab specialising in atomic layer deposition (ALD) as a technique for novel electro- and photocatalyst development. Ludmilla completed her PhD in Chemistry and Chemical Engineering at EPFL (Switzerland) in June 2016 under the supervision of Prof. Michael Grätzel. She then joined Imperial College as a postdoctoral researcher and shortly after became Marie Skłodowska-Curie Individual Fellow with Prof. James Durrant working on understanding photochemistry and photophysics in semiconductors applied in photoelectrocatalysis and photovoltaics.
About Energy Futures Lab
Energy Futures Lab is one of six Global Institutes at Imperial College London. The institute was established to address global energy challenges by identifying and leading new opportunities to serve industry, government and society at large through high quality research, evidence and advocacy for positive change. The institute aims to promote energy innovation and advance systemic solutions for a sustainable energy future by bringing together the science, engineering and policy expertise at Imperial and fostering collaboration with a wide variety of external partners. The Energy Futures Lab daytime seminars are delivered by staff and students from across the College and further afield.