469311 Nanocrystal Doping Stabilizes the Perovskite Phase of Cesium Lead Iodide

Monday, November 14, 2016: 8:00 AM
Golden Gate 5 (Hilton San Francisco Union Square)
Subham Dastidar1, David A. Egger2, Liang Z. Tan3, Samuel B. Cromer1, Andrew D. Dillon1, Shi Liu3, Leeor Kronik2, Andrew M. Rappe3 and Aaron Fafarman1, (1)Dept. of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, (2)Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth, Israel, (3)Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA

All-inorganic, perovskite-phase cesium lead iodide is a promising material for photovoltaics. However, under ambient conditions it rapidly transforms to a non-functional, so-called yellow phase. Here we demonstrate more than two orders of magnitude improvement in the stability of nanostructured perovskite-phase cesium lead iodide thin films through a nanocrystal doping approach. The doped, functional perovskite phase is synthesized by co-assembling cesium lead iodide nanocrystals with cesium lead chloride dopant nanocrystals. The resulting doped nanocrystal solid is subsequently fused into a polycrystalline thin film by chemically-induced, room-temperature sintering. This process ensures nanometer-scale mixing even at compositions that exceed the bulk miscibility of the two constituents. Spectroscopy and X-ray diffraction indicate that some of this chloride is further dispersed during sintering and a polycrystalline mixed phase is formed. By comparison to DFT-calculated values, the relative change in band gap and the lattice contraction are shown to be consistent with a Cl:I ratio of a few percent in the mixed phase.

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See more of this Session: Nanostructured/Thin Film Photovoltaics
See more of this Group/Topical: Materials Engineering and Sciences Division