Intrinsic Properties of Multi-Layer TiO2/V2O5/TiO2 Coatings Prepared via E-Beam Evaporation

• Published in: Materials Vol. 15; no. 11; p. 3933
• Main Authors: Rehman, Irfa, Hanif, Muhammad Bilal, Alghamdi, Abdulaziz Salem, Khaliq, Abdul, Halim, K. S. Abdel, Subhani, Tayyab, Motola, Martin, Khan, Abdul Faheem
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 31.05.2022; MDPI
• Subjects: Air conditioning; Alternative energy sources; Backscattering; Crystal structure; Diffusion layers; Efficiency; Electron beams; Energy gap; Evaporation; Glass substrates; Heat; Molecular beam epitaxy; Morphology; multi-layer; Multilayers; Nanocomposites; Optical properties; Partial pressure; Phase transitions; Photovoltaic cells; Purity; Radiation; Renewable resources; Rutherford backscattering (RBS); Scanning electron microscopy; Solar energy; solar water heater; Stoichiometry; Substrates; Thickness; Thin films; TiO2; Transmittance; V2O5; Vanadium pentoxide-Titanium dioxide; Water heaters
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15113933

Nanocomposite multi-layer TiO2/V2O5/TiO2 thin films were prepared via electron-beam evaporation using high-purity targets (TiO2 and V2O5 purity > 99.9%) at substrate temperatures of 270 °C (TiO2) and 25 °C (V2O5) under a partial pressure of oxygen of 2 × 10−4 mbar to maintain the stoichiometry. Rutherford backscattering spectrometry was used to confirm the layer structure and the optimal stoichiometry of the thin films, with a particle size of 20 to 40 nm. The thin films showed an optical transmittance of ~78% in the visible region and a reflectance of ~90% in the infrared. A decrease in transmittance was observed due to the greater cumulative thickness of the three layers and multiple reflections at the interface of the layers. The optical bandgap of the TiO2 mono-layer was ~3.49 eV, whereas that of the multi-layer TiO2/V2O5/TiO2 reached ~3.51 eV. The increase in the optical bandgap was due to the inter-diffusion of the layers at an elevated substrate temperature during the deposition. The intrinsic, structural, and morphological features of the TiO2/V2O5/TiO2 thin films suggest their efficient use as a solar water heater system.