Hydrothermal synthesis and thermochromic applications of VO2(M) nano-powders

Vanadium dioxide (VO2) is one of the most promising thermochromic candidate for smart windows and energy-efficient coating due to its reversible metal-insulator transition (MIT), which causes a significant change in near-infrared (IR) optical transmittance. Especially, the monoclinic phase (M1) of VO2 shows a reversible phase transition into the rutile VO2(R) phase around 68°C, which makes it attractive for passive solar-control applications. This thesis focuses on hydrothermal synthesis, and processing of VO2(M) nano powders for thermochromic applications. Main attention is focused on the development of the hydrothermal synthesis, which aims to obtain pure VO2(M) with controlled structural and morphological properties. The synthesized products are characterized through X-ray diffraction (XRD), UV-Vis-NIR spectroscopy, and complementary morphological analyses in order to evaluate their phase composition, optical behaviour, and thermochromic performance. Simultaneously, polymer-assisted coating approaches are investigated to improve the dispersion of nanoparticles, film uniformity, and processability for smart-windows applications. Different composite systems are investigated for the fabrication of thermochromic coating, with particular attention to coating homogeneity, optical response, and film formation. Overall, this thesis aims to provide a reliable pathway for the synthesis and integration of VO2(M)-based thermochromic materials which suitable for energy-efficient smart coatings and solar-control window applications.