Scalable flow hydrothermal synthesis of monoclinic vanadium dioxide nanoparticles without reducing agents for thermochromic film

• Continuous hydrothermal flow synthesis enables rapid formation of high-crystallinity VO 2 nanoparticles within seconds. • Reaction temperature and residence time play key roles in controlling particle size and crystallinity. • The thermochromic performance of composite films is governed by nanoparticle microstructure. • The developed flow-based approach offers a scalable route toward thermochromic smart window materials. Monoclinic vanadium dioxide (VO 2 (M)) is a promising thermochromic mater