Mohite, Aditya D.2021-08-272022-02-012021-082021-08-23August 202Li, Wenbin. "Understanding the structural properties in two-dimensional halide perovskites under external stimuli." (2021) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/111341">https://hdl.handle.net/1911/111341</a>.https://hdl.handle.net/1911/111341Understanding the structural and electrical behaviors of organic-inorganic (hybrid) halide perovskites under practical environments is critical for building an efficient and stable optoelectronic device. In this thesis, we report a light-activated interlayer contraction in 2D hybrid halide perovskite. This effect is reversible and is strongly dependent on the structural phase and interlayer distance. X-ray photoelectron spectroscopy and density function theory simulation suggest that photogenerated hole carriers are accumulating at the inter-slab iodide atoms which results in the enhancement of interlayer I---I interactions across the organic barrier. In-situ structural (device) and transport (space charge limited current-SCLC) measurements directly correlate the light-induced interlayer contraction to the onset of a three-fold increase in carrier mobility and conductivity. Furthermore, light intensity dependent SCLC measurement reveals a percolation based mechanism for the enhancement of the charge transport. The increase in transport properties boost the photovoltaic efficiency of Dion-Jacobson 2D n=4 perovskite solar cells from 15.6% to 18.3%.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Perovskiteoptoelectronic devicesexternal perturbationgrazing incident wide angle X-ray scattering.Thesis2021-08-27