Abstract
Metal halide perovskite thin films have achieved remarkable performance in optoelectronic devices but suffer from spatial heterogeneity in their electronic properties. To achieve higher device performance and reliability needed for widespread commercial deployment, spatial heterogeneity of optoelectronic properties in the perovskite thin film needs to be understood and controlled. Clear identification of the causes underlying this heterogeneity, most importantly the spatial heterogeneity in charge trapping behavior, has remained elusive. Here, a multimodal imaging approach consisting of photoluminescence, optical transmission, and atomic force microscopy is utilized to separate electronic heterogeneity from morphology variations in perovskite thin films. By comparing the degree of heterogeneity in highly oriented and randomly oriented polycrystalline perovskite thin film samples, we reveal that disorders in the crystallographic orientation of the grains play a dominant role in determining charge trapping and electronic heterogeneity. This work also demonstrates a polycrystalline thin film with uniform charge trapping behavior by minimizing crystallographic orientation disorder. These results suggest that single crystals may not be required for perovskite thin film based optoelectronic devices to reach their full potential.
Original language | English |
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Pages (from-to) | 6271-6278 |
Number of pages | 8 |
Journal | Nano Letters |
Volume | 18 |
Issue number | 10 |
DOIs | |
State | Published - Oct 10 2018 |
Funding
J.J.C. and S.-H.L. acknowledge support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0016144. The work at ORNL was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division (Y.-Z.M. and B.D.), and the U.S. Department of Energy, Office of Science Graduate Student Research program (B.J.F.). Part of the research was performed as a user project at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. This work is based upon research conducted at the Cornell High Energy Synchrotron Source (CHESS), which is supported by the National Science Foundation under award DMR-1332208.
Keywords
- Lead halide perovskites
- crystallographic orientation
- heterogeneity
- trap sites