Indium oxide (CAS number 1312-43-2), is a semiconducting metal oxide with a bandgap of around 3 eV. Indium oxide can be doped by various metals to afford transparent conducting oxide such as ITO. Indium oxide offers high electron mobility up to 100 cm2/V·s, making it an ideal material for high performance field effect transistors (FETs). Due to its wide bandgap, indium oxide has high optical transparency (transmittance of 70–80%) with refractive index of 2.0.
Indium oxide is also used as an interconnect layer for tandem solar cells. Compared to Ag or Au, indium oxide does not introduce notable optical losses as an interconnect layer in tandem solar cells. This boosts the external quantum efficiency (EQE) of the organic back-cell, leading to an improved overall short-circuit current (Jsc) by approximately 1.5 mA/cm2.
In lithium batteries, indium oxide suppresses the growth of lithium dendrites on the anode, improving cyclic stability (with a capacity retention above 80% after 600 cycles).