Tungsten-doped Vanadium Dioxide Nano Powder

Vanadium dioxide (VO₂) is a well-known phase change material with superparamagnetism, non-linear current/voltage properties and reversible infrared light response characteristics. In order to reduce the reversible phase transition temperature of vanadium, tungsten doping is usually needed to improve its structure. With phase transition, the electrical conductivity, infrared transmittance, resistivity and reflectivity of tungsten-doped M-phase VO₂ will change abruptly, which makes tungsten-doped VO₂ have wide application prospects in intelligent temperature-controlled films, thermistor materials, photoelectric switch materials, infrared detection materials and other fields.

After optimization, a method of preparing tungsten doped two vanadium oxide nano powder by inorganic sol gel method is proposed.

In step 1, the corresponding amount of vanadium pentoxide and ammonia tungstate were weighed according to the composition ratio of V_0.99W_0.01O₂, then mixed and placed at 830 ℃ and melted for 20 minutes. The melt was immersed in the quenching medium and stirred for 12 hours, then aged for 10 days. Among them, the quenching medium was deionized water (or distilled water), and the doped sol was obtained.

In step 2, the polyethylene glycol (PEG) aqueous solution with a concentration of 23 wt% was added into the doped sol and stirred for 8 hours. The volume ratio of PEG aqueous solution to the doped sol was 4:1, and PEG was PEG 6000 to obtain the mixed solution. The mixed solution was then placed in a closed state and hydrothermal reaction was carried out at 180 ℃ for 48 hours to prepare flaky tungsten-doped vanadium dioxide nano powder.

As a further improvement of the preparation method of tungsten-doped vanadium dioxide nano powder, the quenching medium is deionized water or distilled water; polyethylene glycol is polyethylene glycol 6000; centrifugal speed is 3000-8000r/min during centrifugal treatment; and the drying temperature is 50-80 ℃ and the time is 24 h.

Compared with the existing technology, the inorganic sol gel method not only realizes the doping of tungsten, but also uses less raw materials and has no pollution source, which not only makes the production cost low, but also has no pollution to the environment, and is suitable for large-scale industrial implementation.

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