Influencing Halide Segregation in Perovskite Nanocrystals via Surface Treatment

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dc.contributor.advisorWong, Cathy
dc.contributor.authorCrawford, Michael
dc.date.accessioned2022-10-26T17:07:09Z
dc.date.issued2022-10-26
dc.description.abstractNanocrystals (NCs) of mixed-halide perovskite materials offer great potential for solar cells and light-emitting devices owing to their unusual defect tolerance and the tunability of their bandgap via size and halide composition. However, widespread adoption of these mixed-halide perovskite materials is prevented by bandgap instability due to segregation of the halides upon exposure to light or electrical current. This segregation creates regions with a narrower bandgap than the well-mixed phase, redshifting the emission spectrum. In this work I describe efforts to prevent this process by chemical treatment of methylammonium lead iodide-bromide (MAPbIxBr3−x) NCs using a mixture of small, stronglybinding ligands. I use transient absorption (TA) spectroscopy to collect dynamics information during halide segregation, informing a computational model used to extract mechanistic information about the halide segregation process. Using this model, I determine that the observed spectroscopic trends are best explained by iodide anions preferentially segregating into a region within the NC, rather than directly toward the NC surface. The mechanistic insight provided by this work will contribute to future approaches to stabilizing the bandgap in mixed-halide perovskite NCs.en_US
dc.description.embargo2023-04-17
dc.identifier.urihttps://hdl.handle.net/1794/27780
dc.language.isoen_US
dc.publisherUniversity of Oregon
dc.rightsAll Rights Reserved.
dc.subjectCore-Shell Heterostructureen_US
dc.subjectGlobal Fitting Analysisen_US
dc.subjectHalide Segregationen_US
dc.subjectNanocrystalen_US
dc.subjectPerovskiteen_US
dc.subjectTransient Absorptionen_US
dc.titleInfluencing Halide Segregation in Perovskite Nanocrystals via Surface Treatment
dc.typeElectronic Thesis or Dissertation
thesis.degree.disciplineDepartment of Chemistry and Biochemistry
thesis.degree.grantorUniversity of Oregon
thesis.degree.leveldoctoral
thesis.degree.namePh.D.

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