Intense pulsed light sintering of vanadium dioxide nanoparticle films and their optical properties for thermochromic smart window

Highlights: • VO₂ nanoink and IPL sintering were utilized for fabrication of thermochromic films. • IPL sintering improves the crystallinity and thermochromic performance of VO₂ films. • Visible and luminous transmittance of VO₂ films is 63.6% and 46.3%, respectively. • VO₂ films exhibit 47% infrared modulation and 11.2% solar transmittance modulation. • IPL sintered VO₂ films facilitate commercialization of thermochromic applications. -- Abstract: As cost-efficient and large-scalable fabrication, solution processing has been developed to prepare vanadium dioxide (VO₂) films for thermochromic smart windows that can modulate infrared radiation in response to changes in ambient temperature while maintaining visible transmittance. Herein, we report for fabrication of VO₂ films from ball-milled VO₂ nanoparticle ink using intense pulsed light (IPL) sintering. The VO₂ films on quartz substrates were prepared by spin coating. The prepared films were sintered by IPL in air with various voltages from 1400 to 2000 V with the fixed conditions of 4 ms, 400 pulses and 1 Hz. IPL sintering of VO₂ nanoparticle ink led to granular films which were sintered at higher voltages since IPL irradiation was able to evaporate solvent including polymers in the ink, and sinter VO₂ nanoparticles. The VO₂ films IPL sintered at 2000 V exhibit luminous transmittance of over 46.3% and solar transmittance modulation of 11.2%. These results reveal that IPL sintering is substantial progress in terms of long-time and high-temperature post annealing for fabrication of solution-based thermochromic films.