MS Defense by Rachel Lawless
THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
GEORGIA INSTITUTE OF TECHNOLOGY
Under the provisions of the regulations for the degree
MASTER’S OF SCIENCE
on Friday, November 18, 2022
will be held the
" Enhanced Solution Growth of Perovskite Single Crystals Through the Use of Solvent Additives and Dopants”
Dr. Zhiqun Lin, Advisor, MSE
Dr. Zhitao Kang, Advisor, GTRI
Dr. Brent Wagner, GTRI
Perovskites have garnered significant research interest due to their high optoelectronic performance, composition tunability, and diverse applications. Traditional single crystal growth methods require high temperatures and expensive precursors and equipment, but recent work with solution-growth methods has worked to reduce the temperature and cost. This reduction has come at a cost to quality and size. This work uses methodical control of the parameters (concentration, temperature, heating rate, evaporation) to increase the crystal size of the perovskites. This work has seen that the equilibrium growth of the perovskite is essential for increasing the crystal size of the system and making single crystals more widely used.
Further enhancement of the perovskite single crystal size and crystal quality was also achieved using dibutyl sulfide as a solvent additive. Dibutyl sulfide helped to control the solution dynamics and slowed down the crystal growth and allowed for larger crystals with a higher crystallinity to form. This enhancement led to an increase in photoluminescence and carrier lifetime. The single crystals were also doped with Ce3+ to gain an understanding of how the Ce affects the properties of the material. It was found that the Ce3+ incorporated well into the crystal and led to a decrease in crystallinity and size due to the increase in defects in the crystal. The band gap and emission were redshifted as Ce was incorporated. The photoluminescence intensity was enhanced, and carrier lifetimes were decreased. It was found that the dibutyl sulfide additive enhanced the crystallinity and performance of the perovskite while Ce doping enhanced the optical performance of the material while introducing defects as well.