Enhanced photocatalytic efficiency of Mg-doped ZnO thin films: a comparative study of methanol and ethanol-based sol-gel synthesis
No Thumbnail Available
Date
2025
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
This study provides a comprehensive comparison of the structural, optical, and electrical properties of Mg-doped ZnO thin
films synthesized using methanol and ethanol as solvents. X-ray diffraction analysis confirmed the hexagonal wurtzite
structure for both cases, with a stronger c-axis orientation in ethanol-derived films. Notably, magnesium incorporation led to
an increase in crystallite size, reaching 23 nm in methanol-based films. Morphological analysis using scanning electron
microscopy (SEM) revealed dense, homogeneous, and smooth surfaces for both solvent-derived films. Optical
characterization indicated a reduction in transmittance for ZnO films synthesized in methanol compared to ethanol-based
films, alongside an increase in the energy band gap (ranging from 3.23 to 3.34 eV) as Mg concentration increased.
Photoluminescence spectroscopy identified UV emission and defect-related peaks in the visible region at room temperature.
Magnesium incorporation was further verified by energy-dispersive spectroscopy (EDS) and Fourier-transform infrared
spectroscopy (FTIR). Electrical and photocurrent measurements demonstrated n-type semiconducting behavior with
enhanced photoresponse sensitivity. The Seebeck coefficient showed a decreasing trend with increasing Mg doping, with
methanol-derived films exhibiting a higher coefficient (−525 μV/K) compared to ethanol-derived films (−400 μV/K).
Despite this, methanol-based films exhibited a higher carrier concentration at the same Mg doping level. Furthermore,
photocatalytic performance was optimized with 9% Mg-doped ZnO films synthesized in methanol, leading to enhanced
degradation efficiency under solar irradiation. These findings emphasize the combined influence of Mg doping and solvent
choice on the functional properties of ZnO thin films, providing valuable insights for their potential applications in
environmental remediation and energy-related technologies.