Nano Tungsten Oxide Quantum Dot Producing Method

Quantum dot, which is semiconductor nano crystal has diameter smaller or closed to Exciton Bohr radius. It is a kind of quasi - zero wiener material composed by few atoms. Quantum dots due to the quantum confinement of electrons and holes, the continuous band structure becomes a discrete level structure with molecular properties that can fluoresce when excited.

Tungsten oxide is a type of n type semiconducting material, has special photochromic, electrochromic, thermochromic and catalytic property. Nano tungsten oxide has good photopic, magnetic, catalytic and chemical activity based on quantum dot, small size, interfacial, superficial, and macroscopic quantum tunneling effect. It has prosperous application in field of biochemical image, photothermal therapy and photocatalysis.

There are a series problems exist in producing method of tungsten oxide quantum dot such as complex producing process, using a large amount of organic solvent, expensive experimental instrument, insufficient property of tungsten oxide quantum dot. To overcome the existing problem, researchers use solvent thermal method to produce fluorescent tungsten oxide quantum dot. Steps are as following.

Weigh 30mg tungsten disulfide powder, dispersed in 45mL of anhydrous ethanol, the dispersion was added 0.1mL hydrogen peroxide, then stirring with a glass rod. The prepared mixture was transferred to a 100mL reactor, sealed at a temperature of 60 ℃, the reaction time was 4h reaction in an oven, then cool to room temperature. The reaction solution was vacuum filtered through a 0.22 μm pore size filter to remove unreacted residual particles, and the filtrate was collected. The filtrate into the cut-off molecular weight dialysis bag 1000D to dialysis for 2 to 3 days. The obtained dialysate was freeze-dried at a temperature of -20 ° C. and a pressure of 20 Pa to obtain tungsten oxide quantum dot powder.

The method for preparing fluorescent tungsten oxide quantum dot by using solvent thermal method is simple in operation, less in time consumption, safe, environment-friendly and high in output. All the raw materials required for the reaction are convenient and available raw materials on the market. The prepared tungsten oxide quantum dots have good dispersibility, high fluorescence stability and many other advantages.

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