This presentation will introduce a novel family of materials based on mixed chalco-halide semiconductors such as pnictogen chalco-halides (Sb,Bi)(S,Se)(Br,I) and anti-perovskite (Ag3(Br,I)) compounds. The first part will be devoted to reviewing the most relevant results reported so far for the few examples available in the literature about these materials, that have reached encouraging conversion efficiencies around 5% within a very limited timeframe, with a meso-porous solar cell configuration.
The second part will be dedicated to present the physical and chemical synthesis of pnictogen chalco-halides, including the fundamental properties of these compounds obtained by DFT modelling will be discussed. The calculation of the bandgaps, band structures, optical and transport properties will be presented, discussing the trends of these properties depending on the chalcogen or the halogen introduced into the structure. The results will show that all these compounds can be relevant for different thin film photovoltaic applications, with bandgaps ranging from 1.6 eV for SbSeBr up to 2.3 eV for BiSBr. In addition, the complexity of the synthesis of mixed chalco-halides will be discussed, and a new methodology for their synthesis, developed by the authors of this work, and based on the combination of co-evaporation of chalcogenides and high-pressure reactive annealing under halogen atmosphere, will be presented. This methodology allowed for the first time the demonstration of working solar cells with absorbers produced by vapor deposition techniques with these compounds. The tunability of the Q1-D structures by changing the synthesis temperature and pressure will be demonstrated.
The last part of the presentation will be devoted to the very last results obtained in the synthesis of a new family of materials so-called antiperovskites, and based on silver chalco-halides. This will include DFT calculations, synthesis by chemical routes, fundamental properties presentation, and first photovoltaic devices demonstration. Finally, the perspective of these materials and the possible advantages with respect to current chalcogenide and halide technologies, will be presented and discussed.
Prof. Dr. Edgardo Saucedo received his PhD in Materials Physic at the Universidad Autónoma de Madrid in 2007. From 2010-2020 he was the Deputy Head of the SEMS Group at IREC working in emerging thin film photovoltaic materials. In 2020 he becomes Professor at the Polytechnic University of Catalonia (UPC).
He holds 5 patents and has co-authored more than 260 papers and more than 400 contributions to International Conferences. He has been involved in more than 40 European and Spanish Projects, and he was the Coordinator of the ITN network Kestcell, the RIA project STARCELL, and the RISE project INFINITE-CELL. In 2019 he was granted with an ERC-Consolidator (SENSATE), for the development of low dimensional materials for solar harvesting applications.
He has supervised 13 PhD Thesis and is currently supervising 10 more. He has an h factor of 48 and more than 8000 citations. In 2020 he has been awarded with the ASEVA-Toyota Award for his contribution to the development of sustainable photovoltaic technologies and the ICREA Academia Award in 2021.