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Shi, Y.J., Zhang, R.J., Zheng, H., Li, D.H., et al. (2017) Optical Constants and Band Gap Evolution with Phase Transition in Sub-20-nm-Thick TiO₂ Films Prepared by ALD. Nanoscale Research Letters, 12, Article No. 243.
https://doi.org/10.1186/s11671-017-2011-2

has been cited by the following article:

• TITLE: Band Gap Energy and Photocatalytic Efficiency of TiO2 Thin Films Deposited via Dip and Spin Coating under Visible Light

  AUTHORS: Zulkifli Mohd Rosli, Nur Dalilah Johari

  KEYWORDS: TiO2 Thin Films, Photocatalysis, Spin Coating, Methylene Blue, Sol-Gel, Dip Coating

  JOURNAL NAME: Journal of Power and Energy Engineering, Vol.13 No.12, December 8, 2025

  ABSTRACT: TiO2 thin films were prepared via a water-based sol-gel method and deposited using dip and spin coating techniques to investigate the relationship between band gap energy and photocatalytic efficiency under visible light irradiation. The influence of deposition method and annealing temperature on the structural phase, optical properties, and methylene blue (MB) degradation performance was examined. Dip-coated films exhibited a transition from anatase to a mixed anatase-rutile phase above 300˚C, while spin-coated films predominantly formed the brookite phase. The band gap of dip-coated films decreased from 2.81 eV at 200˚C to 2.48 eV at 500˚C, whereas spin-coated films showed a minimum of 2.45 eV at 300˚C, achieving the highest MB degradation efficiency of 97.7%. Higher temperatures led to band gap widening and reduced photocatalytic activity. These findings demonstrate that spin-coated TiO2 thin films annealed at 300˚C exhibit optimal structural and optical properties for visible-light-driven photocatalysis.