Research Article
On the Kerr Effect and Optical Bistability of Graphene Based Spherical ZnO@Ag Core-Shell Nanocomposite
Gashaw Beyene*
Issue:
Volume 13, Issue 2, June 2025
Pages:
27-34
Received:
25 October 2025
Accepted:
6 November 2025
Published:
9 December 2025
Abstract: The drawback of one type of material can be modified by incorporating it with another suitable material. One of the mechanisms to enhance the properties and overcome the drawbacks of a material is by forming a core-shell nanostructure. Core–shell nanocomposites are one of the most preferable structures used to overcome the drawbacks of one material and enhance the properties of another. Graphene monolayer (GML), zinc oxide (ZnO), and silver (Ag) nanomaterials are highly recommended for optical-based applications and for enhancing the properties of other materials. Using a quasi-static approximation framework, we examine the optical response of a graphene monolayer-based ZnO@Ag spherical core-shell nanocomposite embedded in a highly compatible dielectric host matrix. The numerical study revealed that optical factors such as the dielectric function of the host medium, filling factor, volume fraction, and graphene’s Fermi energy greatly impact the nanocomposite’s local field enhancement factor, optical bistability, and hysteresis response. The graphene monolayer-wrapped ZnO@Ag spherical core-shell nanocomposite exhibits a strong nonlinear optical response in the visible spectral region. A low bistability threshold in the visible range was achieved by adjusting key parameters and utilizing Kerr-nonlinear graphene with silver as the outer shell, which enhances the nonlinear effect. These findings imply that core-shell nanostructures made with two-dimensional materials such as graphene have a unique advantage for plasmonic and optical device optimization, data storage application.
Abstract: The drawback of one type of material can be modified by incorporating it with another suitable material. One of the mechanisms to enhance the properties and overcome the drawbacks of a material is by forming a core-shell nanostructure. Core–shell nanocomposites are one of the most preferable structures used to overcome the drawbacks of one material...
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Research Article
Micro Array of Fresnel Lenses Concentrator Photovoltaic System on Crystalline Silicon Solar Cells
Nura Liman Chiromawa*,
Kamarulazizi Ibrahim
Issue:
Volume 13, Issue 2, June 2025
Pages:
35-45
Received:
7 November 2025
Accepted:
19 November 2025
Published:
17 December 2025
DOI:
10.11648/j.ajop.20251302.12
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Abstract: Using the combination of the electron beam lithography (EBL), the reactive ion etching (RIE) and the Polydimethylsiloxane (PDMS) replica molding techniques the author have fabricated the micro-array of PMMA/SiO2 Fresnel lenses concentrator photovoltaic CPV-system for high efficiency silicon solar cells. Fresnel rings units containing eleven concentric rings were created on PMMA layer with the outermost Fresnel ring having an external diameter of 45.24μm and are located ≈200μm away from each other. The CPV-system consists ≈3025-Fresnel lens units per cm2 with approximate focal length f of ≈45 μm and the optical concentration ratio (OCR) of ≈95X. The resulting CPV-system when placed at the location ≈45 μm from the surface of silicon solar cells (Si-Solar cells) increased the open circuit voltage VOC by 17.9 mV, short current density JSC by 5.2 mA/cm-2 and the maximum power Pmax by 11.42 mW. Meanwhile, this system enhanced power conversion efficiency of Si-Solar cells by 0.17% and decreased the series resistance Rs of Si-Solar cells by 0.81 Ω.
Abstract: Using the combination of the electron beam lithography (EBL), the reactive ion etching (RIE) and the Polydimethylsiloxane (PDMS) replica molding techniques the author have fabricated the micro-array of PMMA/SiO2 Fresnel lenses concentrator photovoltaic CPV-system for high efficiency silicon solar cells. Fresnel rings units containing eleven concent...
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