Tungsten Oxide Metal Doping

Metal doping refers to a variety of substances mixed together. In the chemical, materials and other fields, doping generally refers to the incorporation of small amounts of other elements or compounds in such materials or substrates to improve the properties of a material or substance. Doped materials, substrates can produce specific electrical, magnetic and optical properties, so that it has a specific value or use.

Doping tungsten oxide regulation band gap is an important means. The purpose of doping is to red shift tungsten oxide absorption edge, reduce the band gap, or to form a band with the state, thereby expanding the light absorption range. Many reports show that rare earth metals, precious metals, transition metals, poor metals can be used for tungsten oxide doping. Metal ions doped to tungsten oxide act as an electron trap to suppress the recombination of photogenerated electrons and holes, thereby increasing the redox potential of photogenerated free radicals, widening the range of light absorption, and improving the quantum efficiency.

But metal-doped tungsten oxide also has some disadvantages, such as thermal instability and expensive ion implantation equipment. In addition, metal doping is also the main cause of partial blockage of surface sites in the photocatalytic reaction. For some p-type metal ions such as aluminum, chromium and other doped tungsten oxide, but also as an electron trap to capture photo-generated electrons. However, once they become negatively charged, positively charged holes are also attracted to recombine with photogenerated electrons, reducing the quantum efficiency. The same can happen with some n-type metal ions once they are positively charged.

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