Strain in Halide Perovskites: Characterisation, Crystallography, Consequences
type: CreativeWork
description: Optoelectronic devices such as solar cells, LEDs, and X-ray detectors making use of halide perovskites as the light absorbing or emitting material have experienced a dramatic increase in efficiency in recent years. As a result, halide perovskite-based solar cells are now starting to make their way out of laboratories and into the commercial market. However, there is still room for efficiency improvements, and in many of the devices that do boast high efficiencies, long-term stability remains a thorny issue for the field. Strain is known to affect the performance of a range of semiconductors, and halide perovskites are no exception. However, the precise links between strain and optoelectronic properties in these materials appeared obscure, with a number of studies in the literature presenting conflicting results. In this thesis, after setting out my motivation in Chapter 1, I make use of a range of synchrotron-based X-ray diffraction techniques to characterise strain in halide perovskites. As introduced in Chapters 2 & 3, this crystallographic approach is combined with photoluminescence (PL) measurements as a probe of optoelectronic performance with the view to understand the consequences of strain in these materials. I primarily employ coherent diffraction techniques, for example using Bragg coherent diffraction imaging in Chapter 4 to image internal strain distributions in halide perovskite devices with nanoscale resolution. In so doing, I find intra-grain and grain-to-grain strain distributions to be remarkably heterogeneous, and I identify dislocations in full solar cell device stacks. Chapter 5 then demonstrates that *in situ* illumination induces striking dislocation migration. Extending my coherent diffraction imaging approach to Bragg ptychography in Chapter 6 allows me to spatially correlate increased tensile strain with red-shifted PL spectra and shorter PL lifetimes in a single crystal of CsPbBr3 purposely isolated from other possible causes of optoelectro…
abstract: Optoelectronic devices such as solar cells, LEDs, and X-ray detectors making use of halide perovskites as the light absorbing or emitting material have experienced a dramatic increase in efficiency in recent years. As a result, halide perovskite-based solar cells are now starting to make their way out of laboratories and into the commercial market. However, there is still room for efficiency improvements, and in many of the devices that do boast high efficiencies, long-term stability remains a thorny issue for the field. Strain is known to affect the performance of a range of semiconductors, and halide perovskites are no exception. However, the precise links between strain and optoelectronic properties in these materials appeared obscure, with a number of studies in the literature presenting conflicting results. In this thesis, after setting out my motivation in Chapter 1, I make use of a range of synchrotron-based X-ray diffraction techniques to characterise strain in halide perovskites. As introduced in Chapters 2 & 3, this crystallographic approach is combined with photoluminescence (PL) measurements as a probe of optoelectronic performance with the view to understand the consequences of strain in these materials. I primarily employ coherent diffraction techniques, for example using Bragg coherent diffraction imaging in Chapter 4 to image internal strain distributions in halide perovskite devices with nanoscale resolution. In so doing, I find intra-grain and grain-to-grain strain distributions to be remarkably heterogeneous, and I identify dislocations in full solar cell device stacks. Chapter 5 then demonstrates that *in situ* illumination induces striking dislocation migration. Extending my coherent diffraction imaging approach to Bragg ptychography in Chapter 6 allows me to spatially correlate increased tensile strain with red-shifted PL spectra and shorter PL lifetimes in a single crystal of CsPbBr3 purposely isolated from other possible causes of optoelectro…
author: Orr, Kieran
language: eng
keywords: Condensed matter physics, Diffraction, Materials, Perovskite, Renewable energy
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/96f9c5bf-5196-4ad1-8a00-cb55d2e95046/download
license: https://creativecommons.org/licenses/by-nc/4.0/
date published: 2024-01-04
date modified: 2026-07-22T22:24:04Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.108243