Abstract

Metal halide perovskites (MHPs) nanocrystals (NCs) have been intensively investigated in recent years for various photonics and optoelectronics applications because of their excellent color tunability, narrow band emission, high luminescence efficiency and simple solution-process capability. However, one big obstacle remains to be overcome, which is their instability problem under external stresses, such as heat, light, moisture or oxygen exposures. In this dissertation, I will firstly discuss an anti-solvent induced one-step, general method to convert low-cost commercial light diffusing polymer microspheres into stable perovskite-on-polymer down-conversion microspheres. The obtained perovskite-polymer microspheres (PPMs) exhibit high color tunability, narrow band emission, excellent water stability, and integrated light diffusion capability. The pure green emitting CsPbBr3 PPMs manifests a high photoluminescent quantum yield photoluminescent quantum yield (PLQY) of 70.6% and their superior stability in water is also demonstrated. By dispersing these PPMs in polydimethylsiloxane (PDMS) matrix, we further obtained a diffusive down-converting sheet, which is capable of turning blue LEDs into homogeneous light sources with a half-value angle(HVA) as high as 50o. These PPMs hold great promise to be applied as a low-cost, high quality replacement for the traditional, expensive remote downconverters. To further enhance the stability of the perovskite-polymer composites (PPCs) and make them compatible with polymer matrices that have a variety of form factors, a newly developed deep-dyeing process will be introduced. With this strategy, we can directly convert commercial solvent-resistant polymer matrices into luminescent PPCs. The achieved full-color deep-dyed PPCs (DDPPCs) have high PLQY (up to 78%), wide color tunability spanning all visible range and superior stability against environmental stimuli, unprecedently surviving water immersion for over 3 years. These approaches result in highly stable functional PPCs of different form factors and pave the way towards real world applications of metal halide perovskites nanocrystals for novel photonic applications, such as displays, solid state lighting and beyond.

Notes

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Graduation Date

2021

Semester

Summer

Advisor

Dong, Yajie

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Materials Science and Engineering

Degree Program

Materials Science and Engineering

Format

application/pdf

Identifier

CFE0008761;DP0025492

URL

https://purls.library.ucf.edu/go/DP0025492

Language

English

Release Date

August 2026

Length of Campus-only Access

5 years

Access Status

Doctoral Dissertation (Campus-only Access)

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Restricted to the UCF community until August 2026; it will then be open access.

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