Indium(III) Oxide: Radioprotective Screens and High-Purity Nanoparticle Formation

Indium(III) oxide is used in some types of batteries, thin film infrared reflectors transparent for visible light (hot mirrors), some optical coatings, and some antistatic coatings. In combination with tin dioxide, Indium(III) oxide forms indium tin oxide (also called tin doped indium oxide or ITO), a material used for transparent conductive coatings. In semiconductors, it can be used as an n-type semiconductor used as a resistive element in integrated circuits. In histology, indium oxide is used as a part of some stain formulations.

Radioprotective Indium (III) Oxide Screens for Mammography Scans

The diagnosis and treatment of cancer remains one of the most pressing concerns engaging scientists worldwide today. This is due to the high prevalence and morbidity percentages in the latter stages, particularly in specific cancer types. Although many types of cancer do not differentiate based on gender, it is well known that some types of cancer are more prevalent in men and some in women. The findings obtained for the Indium(III) oxide-doped glass screen were compared to those obtained for the protective screen proposed by Koo and Lee, and the results obtained were analyzed. During mammography, a lead-acrylic protective screen is recommended to reduce radiation exposure to the unexposed breast. Objectives: This research study aimed to construct an Indium(III) oxide-rich tellurite-glass screen (TZI8) and compare its performance to that of lead acrylic. A three-layer heterogeneous-breast phantom was developed, using the MCNPX (version 2.7.0) Monte Carlo code. An MCNPX-simulation geometry was designed and implemented, using the lead-acrylic and TZI8 shielding screens between the right and left breast. Next, the reliability of the phantom and the variations in absorption between the lead-acrylic and Indium(III) oxide-rich tellurite-glass screen were investigated.[1]

Before the primary assessment step, in which the phantom and protective screens provide the changes in the amount of energy deposited in the unexposed breast, the transmission factors of the used protective screens were calculated. This computation was reviewed as a preliminary step, and the primary photon-flux reductions through the protective Indium(III) oxide-rich tellurite-glass screen and lead-acrylic shielding screens were computed and firstly compared with the following phase of calculations. However, the value obtained for TZI8 in secondary-flux amount is much smaller. This difference caused the TF values to change correspondingly, leading the 0.1460 value for lead acrylic to decline to 0.0308 levels for Indium(III) oxide-rich tellurite-glass screen, and a tendency to decrease by around 80%. Through a comparison with a lead-acrylic protection screen that has recently been recommended for breast protection during mammography examinations, our research team designed an Indium(III) oxide-rich tellurite-glass screen as a shielding material to be similar to the situations under which the lead-acrylic screen was analyzed.

Formation of High-Purity Indium Oxide Nanoparticles

Indium(III) oxide (In2O3) nanostructures have a direct bandgap of 3.55–3.75 eV with versatile applicability to selective sensors, solar cells, flat-panel displays, and photocatalytic devices. The wide band gap of In2O3 suggests their potential applicability under room temperature conditions, like other wide band gap semiconductors, e.g., GaN, ZnO, TiO2, and diamond. Use of polystyrene beads, polymethylmethacrylate, and carbon materials has been reported in hard template-based synthesis, whereas vesicles, microemulsion droplets, and micelles have been used in soft template-based synthesis. In the preparation of Indium(III) oxide particles, application of the former was preferred over the latter due to superiority in terms of size, shape, shell thickness, and surface morphology. The application of Indium(III) oxide nanoparticles for sensing ammonia has been demonstrated by many researchers. However, most of those reported sensors were designed to operate at elevated temperatures. In some cases, response times of 30 s or more have been reported. Other studies have also addressed the possibility of sensing ammonia under room temperature conditions without providing detailed information. Ti4+ ion doped Indium(III) oxide has also been proposed for such an application with the detection of NH3 in the 5–1000 ppm range.[2]

High-purity Indium(III) oxide nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles were investigated to support the formation of the desired products. These Indium(III) oxide nanoparticles were used for sensitive sensing of ammonia gas using a four-probe electrode device. The proposed sensor offered very quick response time (around 10 s) and highly sensitive detection of ammonia (at a detection limit of 1 ppm).

References

[1]ALMisned G, Elshami W, Kilic G, Ilik E, Rabaa E, Zakaly HMH, Ene A, Tekin HO. Exploring the Radioprotective Indium (III) Oxide Screens for Mammography Scans Using a Three-Layer Heterogeneous Breast Phantom and MCNPX: A Comparative Study Using Clinical Findings. Medicina (Kaunas). 2023 Feb 9;59(2):327. doi: 10.3390/medicina59020327. PMID: 36837529; PMCID: PMC9964137.

[2]Bhardwaj SK, Bhardwaj N, Kukkar M, Sharma AL, Kim KH, Deep A. Formation of High-Purity Indium Oxide Nanoparticles and Their Application to Sensitive Detection of Ammonia. Sensors (Basel). 2015 Dec 17;15(12):31930-8. doi: 10.3390/s151229895. PMID: 26694415; PMCID: PMC4721814.