Please post and forward to your groups: ---------------------------- CENTER FOR EXCITONICS SEMINAR SERIES: PEROVSKITE SEMINAR: Progress of Planar Perovskite Solar Cells for Efficiencies above 20% Wed. November 2, 2016 at 3:30 PM/ 36-462 Juan-Pablo Correa-Baena Massachusetts Institute of Technology, Department of Mechanical Engineering [j.correa-epfl] Perovskite solar cells (PSCs) have achieved certified power conversion efficiencies (PCEs) of 22.1% by low cost and low temperature solution processing. The highest efficiency perovskites are Pb-based with mixed MA/FA cations and Br/I halides and a high-temperature-processed mesoporous TiO2 layer. The simplification of PSCs by replacing the mesoporous electron selective layer (ESL) with a planar one, is advantageous for large-scale manufacturing. The planar configuration is composed of a simple stack of conductive glass, electron selective, perovskite, and hole transport layers, topped by a metal electrode. However, these low cost, low temperature mesoporous-free planar devices have struggled to keep up the high efficiencies garnered by their mesoporous counterparts. Recent breakthroughs by some of us in the community have changed this dynamic, showing that highly efficient planar PSCs are possible by understanding energetics and improving processing. Employing atomic layer deposited SnO2 as the electron selective layer yielding efficiencies of 19.5% have been demonstrated. More recently, a breakthrough in solution-processed SnO2 planar devices has yielded a record for planar PSCs of 21%. In this talk I will show some of the work that my colleagues at EPFL and I have pushed forward to achieve these results while understanding some of the underlying mechanisms in PSCs. In particular, the role interfaces play in recombination dynamics will be discussed. Dr. Juan-Pablo Correa-Baena is a postdoctoral researcher in the group of Prof. Tonio Buonassisi at the Massachusetts Institute of Technology (MIT). Before joining MIT, he spent two years as a postdoctoral researcher in the groups of Profs. Anders Hagfeldt and Michael Grätzel at the Ecole Polytechnique Fédérale de Lausanne (EPFL). Originally from Colombia, he pursued his higher education studies at the University of Connecticut, USA. His PhD work focused on the study of porous metal oxide materials, in particular, transparent conducting aerogels, and their application in dye-sensitized solar cells. At EPFL he worked on perovskite solar cell research focusing on understanding the interfacial dynamics between the perovskite materials and the electron and hole selective layers and developing new strategies to improve efficiency in planar perovskite solar cells. The Center For Excitonics Is An Energy Frontier Research Center Funded By The U.S. Department Of Energy, Office Of Science And Office Of Basic Energy Sciences Light refreshments will be served.