Open Access

ARTICLE

Structural and optical properties of ZnS/rGO nanocomposites optoelectronic devices

A. M. Abdel-Daiem^a, M. Ahmed^a,, E. R. Shaaban^b,

a Department of Physics: Faculty of Science, King Abdulaziz University, 80203, Jeddah, Saudi Arabia
b Physics Department: Faculty of Science, Al-Azhar University, P.O. 71452, Assiut, Egypt

* Corresponding Author:

Chalcogenide Letters 2025, 22(2), 131-142. https://doi.org/10.15251/CL.2025.222.131

Received 31 October 2024; Accepted 06 February 2025;

Abstract

This paper investigates the impact of reduced graphene oxide (rGO) addition on the structural and optical properties of ZnS nanocomposites. The study began with the synthesis of graphene oxide (GO) through the oxidation of natural graphite powder. This process involved using potassium permanganate in a mixture of sulfuric and phosphoric acids, maintained at 50°C for 48 hours. The reaction was terminated using hydrogen peroxide, followed by purification and drying, yielding 1.5 grams of GO. The preparation of ZnS/GO nanocomposites involved dissolving zinc acetate and varying quantities of GO in water, adjusting the pH, and incorporating sodium sulfide. This mixture underwent heating in an autoclave at 180°C for 12 hours, followed by washing and freezing, resulting in ZnS-RGO composites with differing GO contents. The resulting products were categorized as ZnS0rGO, ZnS-5rGO, ZnS-10rGO, ZnS-15rGO, and ZnS-20rGO. To characterize these composite samples, the researchers employed several analytical techniques, including thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, X-ray Photoelectron Spectroscopy (XPS), and UV-vis spectroscopy. This comprehensive approach allowed for a thorough examination of the effects of rGO incorporation on the nanocomposite's properties. The X-ray diffraction (XRD) results showed increased diffraction intensity with higher rGO content, attributed to improved crystallinity. The crystallite size and lattice strain also increased, with rGO providing nucleation sites. Optical analysis revealed that rGO increased absorbance and decreased the optical band gap, likely due to enhanced free charge carriers. The extinction coefficient and nonlinear refractive index both increased with rGO content, attributed to rGO’s high polarizability and light-matter interactions.

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