Dear Kaushalya, thank you for your very interesting technical question. In this context it should be noted that vanadium has a variety of oxidation states ranging from –3 to +5. Clearly the best known vanadium oxide is the pentoxide V2O5. However, the oxide exhibiting thermochromism is the vanadium(IV) dioxide, VO2. You can find a highly useful review article about thermochromic VO2 right here on RG. Please have a look at the following link:

Advances in Thermochromic Vanadium Dioxide Films

Article Advances in Thermochromic Vanadium Dioxide Films

This paper has been posted as public full text on RG so that it can be freely downloaded as pdf file.

Good luck with your research!

i-vanadium pentoxide (V2O5) Films grown on silicon, glass, and metal substrates by metal organic chemical vapor deposition,Temperature-dependent UV–vis spectroscopy and X-ray diffraction allow the correlation between the reversible continuous red shift of the absorption and the anisotropic thermal expansion along the (001) direction, that is, perpendicular to the sheets constituting the layered structure. Furthermore, the possibility of tuning the thermochromic behavior was demonstrated via a chemical doping with chromium.

Dear Noor, Thank you so much!

Article Visible Thermochromism in Vanadium Pentoxide Coatings

Article Advances in Thermochromic Vanadium Dioxide Films

https://iopscience.iop.org/article/10.1088/1742-6596/559/1/012001/pdf

https://www.routledge.com/Vanadium-Dioxide-Based-Thermochromic-Smart-Windows/Long-Gao/p/book/9789814877060

few articles

goodluck Kaushalya

Thank you so much Dear Dr.Nishantha.