In2O3based

In2O3-based materials are compounds and composites built on indium oxide (In2O3). They include undoped In2O3 and doped variants in which indium is substituted or augmented by elements such as Sn, Ga, Zn, or Ti. Doping and nanostructuring produce transparent conducting oxides with high electrical conductivity and visible transparency, widely used as electrodes in displays and solar cells and as components in sensors and photocatalysts.

In2O3 has a cubic bixbyite structure and a bandgap around 3.6 eV. Doping increases carrier concentration and mobility; oxygen vacancies can donate electrons, boosting conductivity but affecting stability and optical properties. Sn-doped In2O3 (ITO) exemplifies high transmittance and low resistivity, suitable for transparent electrodes. Nanoscale forms and heterostructures with other oxides enhance surface area, gas-sensing response, and charge separation.

Common synthesis methods include chemical vapor deposition, sputtering, sol-gel, hydrothermal/solvothermal routes, and pulsed laser deposition. Doping is achieved during synthesis by precursors; oxygen partial pressure tunes vacancy concentration. Controlling morphology yields nanorods, nanowires, and nanosheets that improve performance in sensors and catalysis.

Applications span transparent electrodes for displays, touch screens, LEDs, and photovoltaics; gas sensing for NO2, CO, and H2; and photocatalysis and solar fuel production, where doped In2O3-based heterostructures enhance charge separation and activity.

Challenges include the cost and supply risk of indium, stability under operating conditions, and the trade-off between conductivity and optical loss. Ongoing research seeks cheaper dopants, alternative oxide systems, and better defect engineering to maintain performance while reducing material costs.