Michele Sessolo is a tenure track researcher (Ramón y Cajal Fellow) at the Institute of Molecular Science (ICMol, www.icmol.es) of the University of Valencia, Spain. He holds a B.Sc. and M.Sc. in Chemistry from the University of Padova (Italy). He later moved to the University of Valencia where he obtained a M.Sc. and Ph.D. in Materials Science working on OLEDs. He has been Marie Curie post-doctoral fellow in the Bioelectronics Dept. at the Ecole des Mines de Saint-Etienne (France), working on the application of organic electronics to biological sensing. Hic current work includes the development of innovative dry processes for the deposition of perovskite thin films, and their application in multilayer devices for photovoltaics and photodetectors.
The most stable and efficient perovskite solar cells reported so far, have mostly been prepared by solution-processing. This is due to the technical difficulties associated with the vacuum deposition from multiple thermal sources. Here we present multi-component materials obtained by using multiple sources (up to 4) thermal vacuum deposition. Different stoichiometries are studied, varying the A-site cations, as well as mixed halide systems. Both narrow bandgap and wide bandgap materials will be presented, with bandgap spanning from 1.5 to 1.8 eV. We highlight the importance of the control over the film morphology and composition, which differs substantially when these compounds are vacuum processed. We identify thermally stable compositions and apply them to opaque and bifacial perovskite solar cells. Avenues to improve the stability and to maximize the open circuit voltage using additives and/or novel charge transport layers will also be discussed.