What Is Indium Oxide?
Indium oxide is an inorganic compound formed by oxidizing indium, primarily used as a semiconductor and in display technologies. It has the chemical formula In2O3, a molecular weight of 277.63, and CAS No. 1312-43-2. It is soluble in acids and insoluble in water. Indium oxide is classified as a Hazardous and Noxious Substance under the Safety and Health Law, a Class 1 Designated Chemical Substance (Class 1 No. 44) under the PRTR Law, and a Hazardous Air Pollutant under the Air Pollution Control Law.
Uses of Indium Oxide
Indium oxide is the primary ingredient in indium tin oxide (ITO), a transparent conductive film created by adding tin oxide. ITO films, utilizing indium oxide, are employed in:
1. Transparent Conductive Films
Used in touch panels for smartphones and tablets, and in display technologies such as LCDs and organic EL panels due to their transparency and electrical conductivity.
2. Solar Cells
Applied as electrodes in solar cells to collect electrons generated by light absorption in semiconductor materials like silicon.
3. Electronic Materials
Utilized in manufacturing electronic components, including LCD backlights and LED electrodes, and in semiconductor production.
Properties of Indium Oxide
Indium oxide, a combination of indium and oxygen, exhibits unique properties, such as transparency to visible light, electrical conductivity, heat resistance, chemical stability, and paramagnetism, making it valuable in the semiconductor and display industries.
1. Transparency
Exhibits high transparency in the ultraviolet to near-infrared wavelength range.
2. Conductivity
Conducts electricity while maintaining transparency, ideal for transparent conductive films.
3. Heat Resistance
Remains stable under high temperatures, suitable for high-temperature manufacturing processes.
4. Chemical Stability
Maintains stability in air and against acids and alkalis.
5. Magnetism
Shows paramagnetism without being magnetized by magnetic fields.
Other Information on Indium Oxide
Indium Oxide Production Methods
1. Thermal Oxidation Method: Metallic indium is oxidized at high temperatures, with oxygen or air supplied to enhance the oxidation. Quality and yield are controlled by adjusting the oxygen flow and temperature.
2. Hydrothermal Method: Water and indium salts are reacted under high temperature and pressure, producing oxides with uniform particle sizes and high crystallinity. Shape variations can be achieved by adjusting reaction conditions.
3. Precipitation Method: Raising the pH of an aqueous solution containing indium ions with an alkaline agent causes a reaction. The resulting precipitate is collected and dried to obtain indium oxide, a method favored for its simplicity and consistent product quality.
Sputtering, a vapor deposition technique, is utilized for creating thin, uniform transparent conductive films.