ORCID
0000-0001-5487-4086
Keywords
Metal halide perovskites, perovskite-polymer composites, radiation detection, tetraalkylammonium manganese(II) bromides, photodynamic therapy, display color conversion
Subject Categories
Materials Science and Engineering | Nanoscience and Nanotechnology
Abstract
Solution-processable luminescent materials have emerged as a versatile platform for engineering light-matter interactions across domains, yet realizing their full potential requires overcoming persistent challenges in stability, toxicity, and processability. This dissertation develops three classes of such materials, metal halide perovskites, zero-dimensional hybrid manganese(II) halides, and colloidal quantum dots, and demonstrates their application across scintillation, display color conversion, and therapeutic light delivery. Perovskite materials have emerged as promising scintillator candidates owing to their X-ray absorption, high light yield, and solution processability; however, single-crystal and nanoparticle forms suffer from environmental instability. Embedding nanoparticles in polymer matrices improves stability, but existing methods remain incompatible with high-barrier hosts such as poly(ethylene terephthalate) (PET). This challenge is addressed through a swelling deswelling strategy incorporating perovskite nanoparticles into PET fibers sourced from commercial tennis strings, yielding composite fibers with an estimated light yield twice that of a commercial reference scintillator, and demonstrating high thermal and moisture stability. An eco-friendly, water-based method for the synthesis of lead-free hybrid manganese(II) bromides is developed, yielding compounds with near-unity photoluminescence quantum yields (PLQYs) and high thermal stability. Their water processability enables pixel-level patterning of this emitter in microchannel plate arrays at 1,954 pixels per inch, demonstrating potential for patterned color converters in Micro-LED displays. The versatility of solution-processable luminescent materials is further demonstrated through CdSe-based quantum dot LEDs (F-QLEDs) developed for antimicrobial photodynamic therapy (aPDT). Unlike conventional aPDT light sources, which are bulky, rigid, and costly with limited spectral tunability, the flexible QLED platform offers conformal contact with wound surfaces, precise spectral matching to the photosensitizer absorption, and skin-safe operating temperatures. Through emission wavelength tuning, thermal management optimization, and improved encapsulation, the F-QLEDs achieved 96% spectral overlap, safe surface temperatures, and shelf-stable performance. In vitro testing demonstrated 9-log reduction of multi-drug resistant Staphylococcus aureus and 2-3 log reduction of Pseudomonas aeruginosa, indicating potential for a wearable bandage for drug-resistant wound infections. These results establish solution-processable luminescent materials as a promising platform for next-generation photonic and optoelectronic applications.
Completion Date
2026
Semester
Summer
Committee Chair
Dong, Yajie
Degree
Doctor of Philosophy (Ph.D.)
College
College of Optics and Photonics
Department
CREOL
Format
Document Type
Dissertation
Language
English
Release Date
8-15-2027
STARS Citation
Jayaprakash Saiji, Shruti, "Engineering Solution-Processable Luminescent Materials For Radiation Detection, Display Color Conversion And Antimicrobial Photodynamic Therapy" (2026). Graduate Studies Theses and Dissertations 2026. 282.
https://stars.library.ucf.edu/gradstudies_etd_2026/282
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