ITQ Severo Ochoa Lecture «Achieving Efficient and Stable Perovskite Solar Cells by Defects Control»

ITQ Severo Ochoa Lecture

El próximo viernes 26 de septiembre de 2025 contaremos con el Prof. Filippo De Angelis –Department of Chemistry and INSTM, University of Perugia, Perugia, Italy. SKKU Institute of Energy Sci. & Tech. (SIEST), SKKU, Korea – quien impartirá la charla “Achieving Efficient and Stable Perovskite Solar Cells by Defects Control”.

Viernes 26 de septiembre de 2025 (12h)
Salón de Actos del ITQ (UPV-CSIC)

Achieving Efficient and Stable Perovskite Solar Cells by Defects Control

Perovskite solar cells are making their way to the market despite intrinsic instability issues remain. Also, replacing lead by less toxic elements remains a major challenge, with tin likely being the only suitable alternative. While lead-based perovskites are affected by instability related to iodide oxidation, tine based materials are plagued by stability of Sn(IV) phases, which are related to the lower oxidation potential of tin compared to lead. A related phenomenon is the stability of tin vacancies, which introduce significant p-doping in tin-halide perovskites, while their lead-based counterpart are essentially intrinsic semiconductors. Defect activity clearly controls doping and could also contribute to the instability towards Sn(IV) phases. Controlling doping and defect activity thus represents a pathway towards obtaining stable perovskites with optimal optoelectronic properties. The different defect activity of tin- and lead-based materials is at the origin of their respective thermal and phot-induced degradation phenomena, including halide demixing and loss of I₂ in lead-halide perovskites.

Here we present results of advanced modelling studies on the defect mediated degradation pathways of prototypical lead- and tin-based materials. We show that iodine chemistry dominates lead-based perovskites while Sn-vacancies are central in promoting both material p-doping and formation of Sn(IV) phases. Interestingly, while p-doping dominates in the bulk, Sn oxidation is only favoured at surfaces or grain boundaries. Thus achieving uniform thin films coupled with proper surface passivation strategies represent a pathway towards achieving more stable THP-based devices. We further unveil the key factors determining the stability of mixed-halide THPs against photoinduced halide segregation phenomena. Molecular and ionic strategies to mitigate p-doping in THPs are also presented.

Prof. Filippo De Angelis

Filippo De Angelis is professor of General and Inorganic Chemistry at the University of Perugia, Italy. He received his M.S. and Ph.D. from the University of Perugia in 1996 and 1999, respectively. He was a post-doc at Princeton University, USA, from 2001 to 2002. He worked as CNR researcher from 2001 to 2018, before joining the University of Perugia as full professor. His research interest are the development and application of quantum mechanical methods to simulation of energy materials and processes. He is the founder and leader of the Computational Laboratory for Hybrid/Organic photovoltaics. He is a highly cited scientist in Clarivate Analytics in 2018-2024, Fellow of the European Academy of Sciences, and Nasini Medal and Malatesta Medal of the Inorganic Chemistry division of the Italian Chemical Society. He is Executive Editor of ACS Energy Letters. He has published over 450 peer-reviewed scientific papers, 7 book chapters, has 3 patent applications, and he is editor of 1 book. His h-index is 114 with >60000 citations on Google Scholar.