Synthesis and Characterization of Multinary Copper Chalcogenide Semiconductor Nanocrystals for Photovoltaic Application

Date of Award

5-5-2024

Degree Name

M.S. in Chemical and Materials Engineering

Department

Department of Chemical and Materials Engineering

Advisor/Chair

Soubantika Palchoudhury

Abstract

There is a continuous thrust for cleaner and more sustainable alternatives for energy conversion with the increasing global energy demand. Among them, photovoltaics, specifically thin film solar cells are highly promising and are one of the fastest growing clean energy technologies in the United States. This research presents the synthesis and characterization of a set of novel multinary copper chalcogenide semiconductor nanocrystals (NCs), CuZn2ASxSe4-x consisting primarily of earth-abundant elements for applications in photovoltaic devices. A modified hot-injection method was used to synthesize these semiconductor NCs containing both S and Se chalcogens. The novelty of the new semiconductor NCs lies in the incorporation of multiple cations as well as two different chalcogen anions within the crystal lattice, which is an achievement from the materials synthesis aspect. The composition-controlled optical and photoluminescence properties of the CuZn2ASxSe4-x NCs were investigated via multi-modal material characterization including x-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence spectroscopy (PL). The crystal structure, as determined from the XRD primarily consisted of the metastable wurtzite (P63mc) phase. The NCs exhibited direct band gap in the visible range that could be tuned both by varying the group III cation within the composition as well as the ratio of S/Se, based on the Tauc plot obtained from the UV-vis characterization. This work lays the groundwork for future investigations into the practical applications of copper chalcogenide NCs in solar energy conversion.

Keywords

Chalcogenide Semiconductors Copper-based Bandgap X-ray diffraction (XRD) Photoluminescence (PL) Nanocrystals Photovoltaics 9.) Solar cells 10.) CuZn2ASXSe4-x 11.) CuZn2InSXSe4-x CuZn2GaSXSe4-x CuZn2AlSXSe4-x Tunable properties

Rights Statement

Copyright 2024, author

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