What part(s) of a mobile phone have Indium Tin Oxide (ITO) coating?
Indium Tin Oxide (ITO) is a ternary composition of Indium (In), Tin (Sn), and Oxygen (O) in varying proportions. ITO is typically encountered with a formulation of 74% In, 18% O2, and 8% Sn by weight. It is transparent and colorless in thin layers, while in the bulk form it is yellowish to grey.
ITO is one of the most widely used transparent conducting oxides because of its electrical conductivity and optical transparency to visible light, as well as the ease with which it can be deposited as a thin film. These properties are utilized to great advantage in touch-screen applications on mobile phones.
Thin films of ITO are most commonly deposited on surfaces by physical vapor deposition. ITO is a mixed of Indium and Tin with a melting point in the range 1526-1926 deg C (1800-2200 K, 2800-3500 F), depending on the composition.
Because of high cost and limited supply of Indium, alternative methods of preparing ITO and alternative materials are being investigated.