WO3

Tungsten trioxide (WO3) is a transition metal oxide semiconductor with a monoclinic crystal structure, commonly used in optoelectronic and electrochromic devices. It is widely employed in smart windows, gas sensors (particularly for NOx and volatile organic compounds), and photocatalytic applications for environmental remediation and water splitting. Engineers select WO3 for its tunable bandgap, strong absorption in the visible-near-infrared spectrum, and ability to reversibly change color and conductivity under applied voltage or light exposure—making it valuable for applications requiring dynamic optical or electrical response with relatively low processing temperatures.