Infrared optical modulation characteristics of W-doped VO2(M) nanoparticles in the MWIR and LWIR regions

Vanadium dioxide (VO2) is a remarkable thermochromic material for application in adaptive infrared camouflage due to the reversible phase transition that is coupled with an abrupt change in infrared optical properties. However, the relatively high phase transition temperature and the unclear infrared optical modulation characteristics in the mid-infrared and far-infrared regions largely restrict its practical applications. Here, W-doped VO2 nanoparticles were successfully prepared to reduce the transition temperature. When the effective doping amount of W was 1.70%, the transition temperature decreased to 43.2 degrees C. Importantly, the infrared properties of W-doped VO2 nanoparticles were studied in both MWIR (3-5 mu m) and LWIR (8-14 mu m) thermal atmospheric windows, for the first time, which exhibited significant infrared optical changes, with emissivity variation of Delta epsilon = 0.17 and Delta epsilon = 0.28, respectively. These favorable results further promote the development of the adaptive camouflage.