Enhanced Version Prepare Nano Tungsten Trioxide with Hydrothermal Method

Tungsten trioxide (WO₃) is a n type semiconductor material with a band gap of about 2.5 to 2.9eV and absorbable wavelengths of 410 to 500nm. The ordered nanostructured tungsten trioxide has the properties of nanomaterials and prominent quantum effects.

The preparation methods of nanometer tungsten trioxide include sputtering, thermal evaporation, chemical vapor deposition, sol-gel, anodic oxidation, template and hydrothermal method. Among them, the hydrothermal method is simple and can synthesize some special structural materials, which is suitable for mass production. Some scholars have improved the traditional hydrothermal method.

Nano tungsten trioxide is prepared by hydrothermal method. The tungstate solution is dissolved in water to form tungstate solution, which is added with hydrochloric acid and solid heteropoly acid in the obtained tungstate solution, stirring until no precipitation, forming a precursor mixture, and adding ammonium oxalate as a structural guide in the precursor mixture and using the FTO substrate as the carrier and through hydrothermal method. After deposition of tungsten trioxide on FTO substrate, tungsten trioxide thin films were prepared by calcining FTO substrates with tungsten trioxide.

0.7mmol K₂WO₄ •2H₂O is dissolved in 30mL deionized water, and 6mL3M HCl solution is added at room temperature. The molar amount of silicotungstic acid is added to potassium tungstate 15%, stirring to white precipitation; 1.8mmol (NH₄) 2C₂O₄ is added as structural guide, and the total volume of ionic water to the solution is 70mL, and the mixing 0.5h is continued. The cleaned FTO conductive glass is tilted into the lining of the reactor. The solution was moved into the reactor and sealed into the air drying oven. The water was heated at 16h at 180 °C and the temperature was cooled to room temperature. The conductive glass was removed, cleaned with deionized water, dried at 60°C and calcined for 0.5h at 600°C, and tungsten trioxide thin films were prepared.

There are few cracks in the tungsten oxide film obtained by the preparation method, which reduces the recombination probability of the electrons and holes, reduces the impedance of the electron transport in the thin film, and thus improves the photoelectric performance of the thin film.

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