The improvement of bilayer VO2/TaOx thermochromic properties for smart window

• Published in: Journal of materials science. Materials in electronics 2022-11, Vol.33 (32), p.24734-24740
• Main Authors: Chen, Dan-ke, Yu, Mao-ze, Hao, Chen-yang, Mi, Wei, Wang, Meng, Zhou, Li-wei, Zhao, Jin-shi
• Format: Article
• Language: English
• Subjects: Bilayers; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystallization; Glass substrates; Magnetron sputtering; Materials Science; Microscopy; Optical and Electronic Materials; Phase transitions; Photovoltaic cells; Smart materials; Solar spectra; Spectrophotometry; Surface roughness; Thin films; Transition temperature; Urban environments; Vanadium oxides; Windows (apertures)
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-022-09180-y

In this paper, the bilayer VO 2 /TaO x structure was investigated to control the solar spectra with the potential application as smart windows in built environments. The VO 2 film was prepared by rapid thermal annealing of the sputtered vanadium thin film on the plain glass substrate. Then the TaO x as the antireflection layer was deposited by reactive magnetron sputtering on the top of the VO 2 thin film. The films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and UV–VIS–NIR spectrophotometry. The VO 2 thin film was well-crystallized and the TaO x layer did not change the preferred growth orientation of VO 2 . The deposition of the TaO x film formed a denser morphology, resulting in reduced surface roughness. The VO 2 /TaO x bilayer could markedly boost the solar regulation efficiency (Δ T sol ) from 6.27 to 12.12% and possesses excellent luminous transmittance ( T lum  = 46.12%). The phase transition temperature for the VO 2 thin film and the bilayer VO 2 /TaO x were 58 °C and 56 °C, respectively, far below 68 °C of bulky VO 2 . The study results provide inspiration for the application of VO 2 in the field of smart windows.