Cadmium Tungstate Nanowires Preparation by Microwave Method

Cadmium tungstate (CdWO₄) single crystal is subordinate to wolframite structure (monoclinic system), and its melting point is 1289 ℃. It is a very important scintillator material with excellent performance, high luminescence efficiency and energy resolution. It can emit light blue to yellow spectra under the action of ultraviolet light. It has been widely used in light emitting diodes and super large screen displays.

At present, the existing preparation methods of CdW nanowires are hydrothermal method. By adding organic surfactants, CdW crystals are oriented to grow and CdW nanowires are obtained. However, this method is not only complex in technology, but also uses a large number of organic surfactants, causing a lot of pollution to the environment, and the length-diameter ratio of CdW nanowires is also small. The sample will reduce the luminescent and damage resistance of CdTW nanowires, which can not meet the user's requirements.

In order to solve the above-mentioned technical problems, some scholars have used microwave method to prepare cadmium tungstate nanowires, and the general contents include:

Step 1: the sodium tungstate is formulated into a solution, the concentration of WO₄^2- ions in the solution is 0.05~2 mol/L;

Step 2: the cadmium chloride is formulated into a solution, the concentration of Cd₂⁺ ions in the solution is 0.05~2mol/L;

Step 3: mixing the sodium tungstate aqueous solution prepared in the first step with the cadmium chloride aqueous solution prepared in the second step, wherein the molar ratio of sodium tungstate to cadmium chloride is 1:1, and the obtained solution is stirred 10-30. After a minute, filter filtration;

Step 4: the precipitate obtained in the third step is placed in the corundum crucible, and then the corundum crucible is placed in a container filled with carbon powder, the carbon powder is surrounded around the corundum crucible, the lid is closed, and the container is moved into the microwave oven;

Step 5: reacting under the action of microwave for 10 to 90 minutes, the power of the microwave oven is 160W to 1000W;

Step 6: After the reaction is completed, the container is taken out, and left to cool to room temperature to obtain a crystallized cadmium tungstate nanowire.

In addition to the heating effect, the microwave preparation process also has a weak polarity and can absorb microwaves. Under the action of microwave, the cadmium tungstate precursor will rapidly heat up in a very short time to obtain crystallization. More excellent cadmium tungstate nanocrystals; in addition, microwaves have a guiding effect on the growth of cadmium tungstate crystals, so that cadmium tungstate crystals are oriented and grown, and finally a cadmium tungstate nanowire with one-dimensional structure can be obtained, tungsten The aspect ratio of cadmium acid nanowires exceeds 50, and the one-dimensional structure has a very large specific surface area and aspect ratio, so that its luminescent properties and damage resistance properties are significantly improved. In summary, microwave method is used. The prepared cadmium tungstate nanowires have broad application prospects in fluorescent, light-emitting diodes, large-screen displays, sensible components, color-developing materials and color-changing materials.

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