Effect of tungsten dopant on structural and thermochromic properties of vanadium dioxide synthesized by hydrothermal method อิทธิพลของสารเจือทังสเตนที่มีผลต่อสมบัติทางโครงสร้าง และเทอร์โมโครมิกของวาเนเดียมไดออกไซด์ที่สังเคราะห์ ด้วยวิธีไฮโดรเทอร์มอล

Abstract

This research is to investigate effect of doping with tungsten (W)  on thermal, and structural properties of synthesized vanadium dioxide (VO₂). VO₂ was synthesized using vanadium pentoxide (V₂O₅)as a precursor and oxalic acid (H₂C₂O₄) as a reducing agent with 1:3 molar ratios by hydrothermal method at 260 °C. W with different weight ratios were added to the initial solution to reduce the phase transition temperature and a subsequent thermal annealing. The as-prepared VO₂ and W-doped VO₂ powder were characterized using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). DSC results showed that Wdoping can decrease phase transition temperature depending on concentration of W. The phase transition temperature was lower to 35 °C when VO₂ doped with 5 wt. % of W.