Optical Band Gap and Urbach Energy of Cobalt-Doped Magnetite Nanoparticles Derived from Loang Balok Iron Sand
Keywords:
Cobalt-doped magnetite, Natural Iron Sand, Tauc plot, Kubelka-Munk, Urbach energy
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.
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References
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[5] K. Saputra, S. Sunaryono, N. V. Difa, S. Hidayat, and A. Taufiq, ‘The effect of Zn doping on thermal properties and antimicrobial of ZnxFe2-xO3 nanoparticles’, AIP Conference Proceedings, vol. 2251, no. 1, p. 040040, Aug. 2020, doi: 10.1063/5.0015679.
[6] A. G. Leonel et al., ‘Tunable magnetothermal properties of cobalt-doped magnetite–carboxymethylcellulose ferrofluids: smart nanoplatforms for potential magnetic hyperthermia applications in cancer therapy’, Feb. 2021, doi: 10.1039/D0NA00820F.
[7] H. Akbi et al., ‘Preventing Agglomeration and Enhancing the Energetic Performance of Fine Ammonium Perchlorate through Surface Modification with Hydrophobic Reduced Graphene Oxide’, ChemistrySelect, vol. 9, no. 1, p. e202301795, 2024, doi: 10.1002/slct.202301795.
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[9] N. Kadian, R. Kumari, A. Panchal, J. Dalal, and D. Padalia, ‘Structural and optical properties of gadolinium doped-magnetite nano-crystal for photocatalytic application’, Journal of Alloys and Compounds, vol. 960, p. 170811, Oct. 2023, doi: 10.1016/j.jallcom.2023.170811.
[10] I. D. Fajariman et al., ‘Comparative Behavior Of Magnetic Iron Oxide Nanoparticles (Mions) Via Mechanical And Chemical Routes’, Indonesian Physical Review, vol. 8, no. 1, pp. 181–195, 2025, doi: 10.29303/ipr.v8i1.407.
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[12] S. Susilawati, A. Doyan, and S. Hadisaputra, ‘Analysis Magnetic Mineral Content of Natural Iron Sand in Beach Island Lombok as Basic Materials of Micro Wave Absorbers’, Jurnal Penelitian Pendidikan IPA, vol. 8, no. 4, pp. 1755–1758, Oct. 2022, doi: 10.29303/jppipa.v8i4.2274.
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[14] A. Taufiq et al., ‘Nanoscale Clustering and Magnetic Properties of MnxFe3−xO4 Particles Prepared from Natural Magnetite’, J Supercond Nov Magn, vol. 28, no. 9, pp. 2855–2863, Sept. 2015, doi: 10.1007/s10948-015-3111-9.
[15] C. Karthikeyan et al., ‘Biocidal chitosan-magnesium oxide nanoparticles via a green precipitation process’, Journal of Hazardous Materials, vol. 411, p. 124884, June 2021, doi: 10.1016/j.jhazmat.2020.124884.
[16] H. Todou Assaouka et al., ‘Copper and iron co-doping effects on the structure, optical energy band gap, and catalytic behaviour of Co 3 O 4 nanocrystals towards low-temperature total oxidation of toluene’, Energy Advances, vol. 2, no. 6, pp. 829–842, 2023, doi: 10.1039/D3YA00082F.
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[18] A. S. Masotti, Á. B. Onófrio, E. N. Conceição, and A. M. Spohr, ‘Uv–vis spectrophotometric direct transmittance analysis of composite resins’, Dental Materials, vol. 23, no. 6, pp. 724–730, June 2007, doi: 10.1016/j.dental.2006.06.020.
[19] B. M. Haque, D. B. Chandra, P. Jiban, I. Nurul, and Z. Abdullah, ‘Influence of Fe2+/Fe3+ ions in tuning the optical band gap of SnO2 nanoparticles synthesized by TSP method: Surface morphology, structural and optical studies’, Materials Science in Semiconductor Processing, vol. 89, pp. 223–233, Jan. 2019, doi: 10.1016/j.mssp.2018.09.023.
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[21] S. Benramache, Y. Aoun, S. Lakel, B. Benhaoua, and C. Torchi, ‘The calculate of optical gap energy and urbach energy of Ni1−xCoxO thin films’, Sādhanā, vol. 44, no. 1, p. 26, Jan. 2019, doi: 10.1007/s12046-018-1003-y.
[22] M. Ledinsky et al., ‘Temperature Dependence of the Urbach Energy in Lead Iodide Perovskites’, J. Phys. Chem. Lett., vol. 10, no. 6, pp. 1368–1373, Mar. 2019, doi: 10.1021/acs.jpclett.9b00138.
[23] M. González-Sánchez, H. Khadhraoui, and ..., ‘Non-enzymatic glucose sensor using mesoporous carbon screen-printed electrodes modified with cobalt phthalocyanine by phase inversion’, Microchemical …, no. Query date: 2025-05-14 09:44:32, 2024, [Online]. Available: https://www.sciencedirect.com/science/article/pii/S0026265X24004260
[24] Y. Zheng, R. Gao, Y. Qiu, L. Zheng, Z. Hu, and X. Liu, ‘Tuning Co2+ Coordination in Cobalt Layered Double Hydroxide Nanosheets via Fe3+ Doping for Efficient Oxygen Evolution’, Inorg. Chem., vol. 60, no. 7, pp. 5252–5263, Apr. 2021, doi: 10.1021/acs.inorgchem.1c00248.
[25] S. Navalón, A. Dhakshinamoorthy, M. Álvaro, B. Ferrer, and H. García, ‘Metal–Organic Frameworks as Photocatalysts for Solar-Driven Overall Water Splitting’, Chem. Rev., vol. 123, no. 1, pp. 445–490, Jan. 2023, doi: 10.1021/acs.chemrev.2c00460.
[26] P. Makuła, M. Pacia, and W. Macyk, ‘How To Correctly Determine the Band Gap Energy of Modified Semiconductor Photocatalysts Based on UV–Vis Spectra’, J. Phys. Chem. Lett., vol. 9, no. 23, pp. 6814–6817, Dec. 2018, doi: 10.1021/acs.jpclett.8b02892.
[27] C. Du et al., ‘In situ synthesis of oxygen-doped carbon quantum dots embedded in MIL-53(Fe) for efficient degradation of oxytetracycline’, Environ Sci Pollut Res, vol. 31, no. 18, pp. 26686–26698, Apr. 2024, doi: 10.1007/s11356-024-32729-9.
[28] P. N. Anantharamaiah and P. A. Joy, ‘Effect of co-substitution of Co2+ and V5+ for Fe3+ on the magnetic properties of CoFe2O4’, Physica B: Condensed Matter, vol. 554, pp. 107–113, Feb. 2019, doi: 10.1016/j.physb.2018.11.031.
[29] D. Mishra, J. Nanda, S. Parida, K. J. Sankaran, and S. Ghadei, ‘Effect of Y3+ and Co2+ co-doping on the structural, optical, magnetic and dielectric properties of LaFeO3 nanoparticles’, J Sol-Gel Sci Technol, vol. 111, no. 2, pp. 381–394, Aug. 2024, doi: 10.1007/s10971-024-06452-3.
[30] A. H. Monfared, A. Zamanian, I. Sharifi, and M. Mozafari, ‘Reversible multistimuli-responsive manganese–zinc ferrite/P(NIPAAM-AAc-AAm) core-shell nanoparticles: A programmed ferrogel system’, Materials Chemistry and Physics, vol. 226, pp. 44–50, Mar. 2019, doi: 10.1016/j.matchemphys.2019.01.016.
Published
2025-12-24
How to Cite
Saputra, K., Inayah, R., Aminy, I., Ardianto, T., & Kurniawidi, D. (2025). Optical Band Gap and Urbach Energy of Cobalt-Doped Magnetite Nanoparticles Derived from Loang Balok Iron Sand. KONSTAN - JURNAL FISIKA DAN PENDIDIKAN FISIKA, 10(02), 1-11. https://doi.org/https://doi.org/10.20414/konstan.v10i02.786
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