Cd3P2 Quantum Dots As Sources for Quantum Emission and Detection of Near-IR Radiation

In recent years, research on quantum dots (QDs) has grown due to their tunable emission and absorbance over a wide range of radiation. However, literature has prioritized researching QDs with band gaps in the visible region as a result of both instrumentation and synthetic challenges. The near-IR region is of particular interest due to applications in medical imaging, communication systems, and military defense. Today, epitaxial InxGa1-xAs QDs are primarily used for the emission and detection of near-IR radiation, yet epitaxial syntheses suffer in terms of scalability, synthetic control, and precursor toxicity. Colloidal QDs (CQDs) appear as an attractive alternative as CQDs are volume scalable, possess greater synthetic control, and are capable of integration into more flexible environments. Lead chalcogenides (e.g., PbS, PbSe), mercury chalcogenides (e.g., HgSe, HgTe), and InAs are the primary near-IR capable CQDs researched, but these species suffer from setbacks such as long carrier lifetimes (>1 µs, PbS/PbSe), toxic precursors and products (HgSe/HgTe), and non-trivial syntheses due to precursor accessibility (InAs). Cd3P2 CQDs stand out as an overlooked competitor as these CQDs possess tunable emission from ~600 nm to 1600 nm, show promise of sub-101 ns lifetimes, and boast simple syntheses with relatively high quantum yields (QYs). The work in this thesis focuses on the characterization and improvement of near-IR capable Cd3P2 CQDs. We have employed a variety of spectroscopic methods to analyze the properties of bare Cd3P2 CQDs. Using transmission electron microscopy (TEM) images and UV-visible absorbance spectra, we show the development of a sizing curve for Cd3P2 CQDs and how this sizing curve can be used to investigate the kinetics of QD syntheses. We have also investigated the effect of surface passivation techniques using CdSe and Zn3P2 on the spectroscopic properties of Cd3P2 CQDs. Our results demonstrate that surface passivation techniques are capable of accelerating radiative lifetimes in Cd3P2 CQDs while maintaining PL QYs and improving air stability. Lastly, as the QYs of CQDs are directly linked with TRPL spectra, we show how measured TRPL spectra of CQDs can be used to predict spectroscopic properties of CQDs, such as QYs and intrinsic radiative lifetimes, using machine learning.

Grantor dc:publisher

University of Alabama Libraries

Year dc:date.issued

2025

Author dc:creator

• Smith, Logan

Advisor dc:contributor.advisor

• Fedin, Igor

Contributors dc:contributor

• Allred, Jared
• Ghosh, Ayanjeet
• Street, Shane
• Araujo, Paulo

• cd3p2
• machine learning
• quantum dots
• quantum yield

Statement dc:rights

• All rights reserved by the author unless otherwise indicated.

Language dc:language.iso

en_US, English

Dc Identifier Other

1176771

OAI identifier oai:identifier

oai:ir.ua.edu:123456789/17063