Regulating NIR reflecting property of hydrothermally synthesized tungsten oxide nanostructures via calcination

Abstract

Present work primarily aims to study the near infrared (NIR) reflecting property of tungsten oxide nanostructures synthesized using hydrothermal method. As-synthesized hydrated tungsten oxide (WO3. H2O) sample was subjected to calcination at temperatures 300, 600, 700, 800 and 900 °C respectively for 1 h and corresponding NIR reflecting performance of the obtained anhydrous tungsten oxide (WO3) nanostructures was analyzed using spectrophotometer. Thermal, structural, morphological, compositional and photoluminescence properties of the nanostructures were also characterized. Moreover, color variation of all samples was identified using CIE L*a*b* color analysis. The sample calcined at 600 °C showed a remarkable NIR reflectance of 91% with color coordinates L* = 70.21, a* = − 4.28, b* = 22.47, h* = 100.78°, and C* = 22.87. Particle size and oxygen vacancies were found to play a significant role in NIR reflectance ability of tungsten oxide. The present work provides new insight into developing NIR reflecting tungsten oxide powders to be used as environmentally friendly cool materials for buildings and automobiles with energy saving performance.