will propose a doctoral thesis entitled,

Crystallization Dynamics and Phase Transformations in

Lead Halide Perovskite Thin Film Processing for Solar Cell

Applications

On

Monday, December 11th at 1:30 p.m.
MRDC Room 3515

and/or

 Virtually via Zoom

https://gatech.zoom.us/j/95524395755

Committee
            Prof. Juan-Pablo Correa-Baena – School of Materials Science and Engineering (advisor)
            Prof. Seung Soon Jang – School of Materials Science and Engineering
            Prof. Matthew McDowell – School of Materials Science and Engineering

            Prof. Natalie Stingelin – School of Materials Science and Engineering
            Prof. Michael F. Toney – University of Colorado Boulder, Chemical and Biological Engineering

Abstract
Lead halide perovskites (LHPs) for perovskite solar cells have the potential to

revolutionize energy conversion with their high efficiencies, accessible precursors, and

relatively inexpensive processing. However, there are two main roadblocks to

commercialization: long term stability, related to the metastable nature of these

perovskite structures, and very specific processing requirements causing problems with

irreproducibility between research groups. The final efficiency and stability of the

perovskite solar cell is largely influenced by the crystal structure of the LHP in the

absorber layer. This crystal structure is influenced by a huge variety of factors from the

composition chosen, solvent used, annealing temperature, rest time between dissolving

precursor powders and spincoating, and many more. In this thesis, I will focus on

understanding crystallization and phase transformations mechanisms of mixed-cation

mixed-halide lead halide perovskites from the initial powders to final devices. Grazing

incidence wide angle X-ray scattering and X-ray diffraction will be used to understand

the crystal structure of final films. Transmission small angle X-ray scattering of

solutions will be used to understand formation of initial crystals in solution that then

translate to changes in crystal structure in the final film. X-ray fluorescence and

cathodoluminescence SEM will connect structure with physical morphology and optical

properties. First principles DFT calculations will be used to corroborate and explain

mechanisms proposed by experimental results.