Monoclinic vanadium (IV) oxide (VO2) has received much attention for applications as intelligent solar control coatings, with the potential to reduce the need for both heating and air conditioning loads within building infrastructure. Chemical vapour deposition-a high-throughput industrially scalable method-is an ideal technology for the deposition of VO2 thin films on window panels. However, these films suffer from poor adhesion and are chemically susceptible to attack. In addition, the VO2 films with optimum solar modulation are unfortunately translucent, restraining their commercial use in energy-efficient fenestration. In this work, multi-functional, robust, layered VO2/SiO2/TiO2 films were quickly deposited on glass substrates using atmospheric-pressure chemical vapour deposition and fully characterised using structural, vibrational spectroscopy and electron microscopy techniques. The VO2/SiO2/TiO2 thin films were designed to exhibit excellent solar modulation properties as well as high transparency and resistance to abrasion, compared to single VO2 films of the same thickness. The films also showed self-cleaning properties comparable to those of commercial Pilkington Activ TM glass, as demonstrated here during the photodegradation of a model organic pollutant (stearic acid). The SiO2 acted as a barrier layer, preventing the diffusion of Ti 4+ ions into the VO2 layer but it also promoted the optical properties and allowed for superior thermochromic behaviour when compared to single VO2 films. The system was modelled to determine the effect of the individual components on the properties of the overall material. It was found that the deposition of the SiO2/TiO2 overlayer resulted in a dramatic improvement of visible light transmission (~30 % increase when compared to single layer analogues) whilst also doubling the solar modulation of the material.

An easy and reproducible method to synthesise thermochromic VO2[M] via VO2[D] at a low calcination temperature.