Tungsten Trioxide (WO3) thin film is a kind of dingal material with large transmittance change, good reversibility, low relative price, long life, non-toxicity and environmental protection, and it is the earliest and most widely used electrochromic material. The application of this electrochromic material is hidden in our daily life. For example, it can be made into smart windows, which can save energy, dim light, control heat load and other dings. Therefore, in order to study the properties of Tungsten Trioxide thin films, researchers have continuously improved their preparation methods, such as preparing WO3 thin films by electrodeposition, which has become a research hotspot in recent years. The following is a general procedure for preparing Tungsten Trioxide thin films by electrodeposition method.
1. Cleaning the ITO substrate
1) 11/4 cm ITO (Indium Tin Oxides) glass sheets were separately isolated and opened into small glass cylindrical beakers;
2) After that, put it in a big glass, and use acetone, methanol, and ultra-pure water for ultrasonic cleaning for 10 minutes to remove dust and adhered organic matter from its surface.
3) After cleaning, put it in a 60 oven for drying, and then measure the conductive side with an ohmmeter, and connect it with a conductive copper tape, which is convenient for the connection of subsequent circuits.
2. Preparation step
1) The solution for electrodepositing Tungsten Trioxide thin film is made of sodium tungstate and inorganic acid. Firstly, 0.125 mol/L
The Na 2WO 4+2 H 2O solution and 1 mol/L perchloric acid solution were prepared.
2) Add 1.2 mL of 1 mol/L HClO 4 to 20 mL of 0.125 mol/L Na 2WO 42 H 2O solution to adjust the pH value of the solution to 1.4;
3) Then, 70 L hydrogen peroxide（H2O2）(30%) was added to prepare the electrodeposition solution.
4) Through the three-electrode system, the prepared ITO substrate is connected to the working electrode, the Pt plate is used as the counter electrode, and Ag/AgCl (3 mol/L KCl) is used as the reference electrode. They were respectively deposited for 400,600 and 1000 seconds at the potential of -0.7 v.
5) Rinse with alcohol and air dry naturally. According to the electrodeposition time, the films were respectively named w 400, w 600 and w 1000.
Compared with other methods, electrodeposition equipment is simpler, the controllability stronger and the coating more uniform.
