Cobalt (Co) is vital to the human body and plays an important role in various biological processes. However, excessive intake of Co compounds has been shown to adversely affect the health of the skin, lungs, and thyroid. Therefore, it is necessary to design a fast, accurate and cost-effective sensor to detect the Co content in drinking water.

Ammonia (NH3) is a gas present in the entire atmosphere in relatively small concentrations (1–5 ppb) and is mainly emitted by human activities. Ammonia causes negative effects to living beings. Therefore, it has been suggested 25 ppm as an allowed exposure level of ammonia concentration. Thus, it is important to find a sensing material for ammonia sensing at room temperature.

Tungsten trioxide (WO3) has been widely applied ain polymorphism, electrochromism and gas phase change. WO3 is also a promising material that can be used for field emission, solar energy and storage.Transition metal oxides (TMO) are used in supercapacitors to increase capacitance and energy density through pseudocapacitance or Faraday mechanism. WO3 is also an excellent transition metal oxide. Although WO3 is a   promising material for supercapacitor electrodes. It lacks chemical stability, yielding low life cycle values.

Tungsten Trioxide (WO₃) is a kind of relatively stable tungsten oxide. Because of its electrochromic, photochromic, gas-chromic and other special properties, WO₃ smart glass is a product that meets the needs of modernization. How to apply Tungsten Trioxide to smart glass?