Theses and Dissertations

ORCID

https://orcid.org/0000-0001-6128-5511

Advisor

Gangishetty, Mahesh

Committee Member

Wang, Kun

Committee Member

Creutz, Sid

Committee Member

Mlsna, Todd

Committee Member

Ariunbold, Gombojav

Date of Degree

5-15-2026

Original embargo terms

Immediate Worldwide Access

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

In recent years, low-dimensional metal halides have garnered significant interest due to their exceptional optical properties. This dissertation focuses on the structural, optical, and photophysical properties of both lead-based and lead-free low-dimensional metal halides and investigates their applications in light-emitting diodes. In Chapter II, the nature of Mn2+ doping in two-dimensional (2D) lead halide perovskites is discussed. 2D perovskites show strong excitonic and dielectric confinement due to their quantum well structures. Introducing optically active Mn²⁺ dopant ions into these 2D perovskites further enhances their optical properties and promotes energy transfer from the host to the Mn²⁺ dopants, resulting in dual emission. However, the effect on the crystal structure remains unclear. This chapter examines how interstitial and substitutional Mn²⁺ doping influences the lattice, including strain and interplanar spacings, using comprehensive XRD analyses, and correlates these changes to their optical properties, such as exciton diffusion and dual emission using transient photoluminescence (PL) spectroscopy and microscopy. Next, low-dimensional ternary copper halide-based LEDs are studied. Among various copper(I) halides, 1D CsCu₂I₃ shows promising broadband emission due to the existence of self-trapped excitons (STEs). However, 1D CsCu2I3 LEDs show a discrepancy between their electroluminescence (EL) and PL, resulting in output colors that differ from the expected colors. Chapter III comprehensively investigates the PL-EL discrepancy and attributes the shift in EL to carrier imbalance in CsCu2I3, arising from differences in ETL electron mobility. To further explore this effect, a resistance to electron mobility is intentionally introduced by adding an interfacial LiF insulating layer. As a result, more red-shifted LEDs are constructed. The CsCu2I3 exhibits broadband yellow emission with a peak at 590 nm, a region highly sensitive to the human eye. Their absorption peaks at around 320 nm, with a large Stokes shift in the PL spectrum, allowing 93.59% transmission of visible light. Chapter IV exploits this property and fabricates bright yellow-emitting 1D CsCu2I3-based transparent LEDs (TLEDs). The optimized devices show an average transmittance of 53.94% across the visible spectrum with an EL peak at ~590 nm. The external quantum efficiencies (EQEs) of these yellow TLEDs are 0.018% and 0.043% for top and bottom emissions, respectively.

Download

Included in

Chemistry Commons

Share

COinS