04/03/2025
By Lalit Saini

The Kennedy College of Sciences, Department of Physics and Applied Physics, invites you to a Master's Thesis defense by Lalit Saini, "Optical Properties of Aluminium (Al) and Copper(II) Oxide (CuO) nanoparticles and their composites."

Date: Wednesday, April 9, 2025
Time: 1 to 3 p.m.
Location: Olney Hall, Room 136D

Advisor:
Mengyan Shen, Ph.D., Department of Physics and Applied Physics, UMass Lowell

Committee Members:
Viktor Podolskiy, Ph.D., Department of Physics and Applied Physics, UMass Lowell
Andriy Danylov, Ph.D., Department of Physics and Applied Physics, UMass Lowell

Abstract:

The optical properties of aluminum (Al) and copper (II) oxide (CuO) nanoparticles, as well as their composites, were thoroughly analyzed in detail using reflection and absorption spectroscopy. Absorption spectra are obtained using Kramers–Kronig (KK) analysis of reflection spectra, enabling accurate identification of optical responses.
Aluminum nanoparticle powder (~50 nm diameter) exhibits localized surface plasmon resonance (LSPR) coupling due to nanoparticle contact, leading to optical absorption in the ~500–1000 nm wavelength range, significantly affecting their optical properties. Within the same wavelength range, CuO nanoparticles (~50 nm diameter) show intense absorption due to interband transitions (O 2p → Cu 3d–4s), a characteristic feature of semiconductor behavior and defect-induced electronic states caused by oxygen vacancies and structural defects.
The objective of this study is to investigate the optical properties of aluminum (Al) and Copper(II) oxide (CuO) nanoparticles individually, as well as to explore the optical characteristics and interfacial interactions that arise from mixing these nanoparticles. Distinct and important spectral features emerge due to the interaction between metallic Al and semiconducting CuO, including plasmonic behavior, interfacial charge transfer, and modifications to the absorption and reflection band-edge properties. These interfacial effects notably alter the optical properties of the metal–oxide nanocomposites.
Overall, these outcomes enhance the understanding of nanoscale metal–oxide interactions and highlight the potential of Al–CuO composites for applications in optoelectronics and plasmon-enhanced materials.