Mohite, Aditya2022-09-232022-09-232022-082022-06-14August 202Torma, Andrew J. "Nano-imaging to Determine the Interstitial Nature of Mn(II) Doping in 2D Halide Perovskites." (2022) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/113224">https://hdl.handle.net/1911/113224</a>.https://hdl.handle.net/1911/113224Andrew Jonathon Torma By performing correlated nanoscale X-ray microscopy, temporally resolved photoluminescence measurements, and magnetic force microscopy on the inorganic 2D perovskite Cs2PbI2Cl2, we show that doping Mn2+ into the structure results in a lattice expansion. The observed lattice expansion contrasts with the predicted contraction expected to arise from the B-site metal substitution, thus implying that Mn2+ does not replace the Pb2+ sites. Photoluminescence and electron paramagnetic resonance measurements confirm the presence of Mn2+ in the lattice, while correlated nano-XRD and X-ray fluorescence track the local strain and chemical composition. Density functional theory calculations predict that Mn2+ atoms reside at the interstitial sites between two octahedra in the triangle formed by one Cl- and two I- atoms, which results in a locally expanded structure. These measurements shed light on the fate of transition metal dopants, local structure, and optical emission when they are doped at dilute concentrations into a wide band-gap semiconductor.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.PerovskitesCrystal structureManganese dopantPhotoluminescenceDensity functional theoryInorganic compoundsDiffractionThesis2022-09-23