Although known for many years, organic-inorganic perovskites and related metal halide-based hybrids have received extraordinary attention recently, due to uniquely diverse chemical components and physical properties, which make them outstanding candidates for applications in photovoltaic and other semiconductor devices. Perovskite structures consist of networks of corner-sharing metal halide octahedra that extend in three or fewer dimensions, providing opportunity to probe how dimensionality of the inorganic framework impacts semiconducting character. Further, incorporation of more complex organic cations enables combining outstanding inorganic-derived semiconducting character with organic-derived properties (e.g., energy level offset, luminescence, chirality, processibility), a feature extending well-beyond what is attainable with established inorganic semiconductors (e.g., Si or GaAs) and underlying the creation of multifunctional hybrids for PV and beyond. This talk will provide a brief historical perspective and introduction to the halide perovskite family, emphasizing chemical/structural versatility and organic-inorganic synergy. Examples of contemporary topics likely to be covered include custom-designed organic cations to template the formation of difficult-to-realize structural paradigms, self-assembly of targeted multilayer quantum wells, and tailored reduced crystallographic symmetry (e.g., to induce spin splitting). Additional examples of organic-inorganic tunability may include controlling hybrid melting temperature to enable solvent-free film preparation and order-disorder transitions (e.g., glass formation and crystallization). Outstanding functionality and versatile processing provide two pillars for future energy, optoelectronic or spintronic application of this exciting materials family.
David Mitzi is the Simon Family Distinguished Professor at Duke University, with appointments to the Departments of Mechanical Engineering and Materials Science and Chemistry. He received his B.S. in Electrical Engineering and Engineering Physics from Princeton University (1985) and his Ph.D. in Applied Physics from Stanford University (1990). Prior to joining the faculty at Duke (2014), Dr. Mitzi spent 23 years at IBM’s Watson Research Center, where his focus was on the search for and application of new electronic materials, including organic-inorganic perovskites and solution-processable inorganic materials for PV, LED, transistor and memory applications. He also served as manager for the Photovoltaic Science and Technology Department, where he initiated/managed a multi-company program to develop a low-cost, high-throughput approach to deposit thin-film chalcogenide-based absorbers for high-efficiency photovoltaics. Dr. Mitzi is a Fellow of the Materials Research Society (MRS), a Clarivate Analytics Highly-Cited Researcher, and recently received the 2020 American Chemical Society (ACS) Award in the Chemistry of Materials for his pioneering work on halide perovskites.