KONSTAN - JURNAL FISIKA DAN PENDIDIKAN FISIKA
Vol 10 No 02 (2025): SCHADULE KONSTAN (Jurnal Fisika dan Pendidikan Fisika)

Optical Band Gap and Urbach Energy of Cobalt-Doped Magnetite Nanoparticles Derived from Loang Balok Iron Sand

Saputra, Kormil (Unknown)
Inayah, Rahmatun (Unknown)
Aminy, Ika Umratul Asni (Unknown)
Ardianto, Teguh (Unknown)
Kurniawidi, Dian Wijaya (Unknown)



Article Info

Publish Date
24 Dec 2025

Abstract

Doping is a practical approach to altering a material's electronic and structural properties, thereby influencing its optical and magnetic characteristics. This study successfully synthesized and characterized cobalt-doped magnetite (Fe2.5Co0.5O4) nanoparticles from natural iron sand via coprecipitation. The main objective was to evaluate the optical properties of the synthesized material using UV-Vis spectroscopy and to compare band gap energies using three approaches: the Tauc method (direct and indirect transitions), the Kubelka–Munk method, and the Urbach energy, an indicator of structural disorder. The characterization results revealed that the incorporation of Co2+ ions into the magnetite structure induced significant changes in the absorption spectra, including the emergence of new peaks and a redshift in the wavelength. The obtained band gap values were 3.71 eV (Tauc-direct), 2.18 eV (Tauc-indirect), and 2.33 eV (Kubelka–Munk), confirming the presence of two types of optical transitions. Furthermore, the relatively low Urbach energy (0.07138 eV) indicated that the crystal structure remained well-preserved despite the modifications induced by doping. This study highlights the importance of employing multi-method approaches for reliable optical characterization and demonstrates that Fe2.5Co0.5O4 materials derived from local resources show promise for photocatalytic and optoelectronic applications.

Copyrights © 2025






Journal Info

Abbrev

konstan

Publisher

Subject

Physics

Description

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