Modified color for VO2/Au/VO2 sandwich structure-based smart windows

In this study, the VO2/Au/VO2 sandwiched structure was fabricated by rapid thermal annealing of sputtered V/Au/V sandwiched structure to modify the intrinsic unpleasant brown–yellow color of VO2 films based on the localized surface plasmon resonance (LSPR) for smart windows. The morphology, crystalline structures, and optical transmittance spectra of the sandwich structure were characterized by scanning electron microscopy, X-ray diffraction and UV-VIS-NIR spectrophotometry, respectively. The obtained results indicate that the VO2/Au/VO2 sandwich structure with different Au nanoparticles sizes shows different color from brown–yellow to blue–green due to the appearance and redshift of LSPR peak. Moreover, the phase-transition temperature for the optimized VO2/Au/VO2 sandwich structure was only 42.5 °C, far below 68 °C for bulky VO2. The optimized VO2/Au/VO2 thin films could simultaneously meet the requirements of comfortable color and a reduced phase-transition temperature, and these excellent features would benefit the practical application of VO2 thin film-based smart windows.