SAIP2026

Synergistic properties and sensing performance of In2O3-based binary and ternary heterostructures for acetone detection

7 Jul 2026, 17:20

1h 20m

Great Hall (University of the Western Cape)

Poster Presentation Track A - Physics of Condensed Matter and Materials Poster Session 1

Speaker

Katlego Morulane (University of the Free State)

Description

The rapid and precise detection of volatile organic compounds (VOCs), particularly acetone (C3H6O), is essential for environmental monitoring, industrial safety, and healthcare diagnostics. Due to the increased morbidity and mortality rates of metabolic diseases (i.e., diabetes), portable advanced n-p and n-p-n SMO-based acetone sensors should be considered for detecting and monitoring low acetone concentrations. This study examines the gas-sensing performance of In2O3-based binary and ternary sensors, focusing on their gas-sensing performance towards low concentrations of C3H6O. The integrated n-p In2O3-Co3O4, In2O3-CuO, In2O3-Mn3O4, and In2O3-NiO binary heterostructures, along with the n-p-n In2O3-Co3O4-CeO2, In2O3-Co3O4-SnO2, In2O3-Co3O4-ZnO, and In2O3-Co3O4-ZrO2 ternary heterostructures, were fabricated using a hydrothermal approach. From a gas-sensing perspective, the n-p In2O3-Co3O4 binary sensor showed impressive performance, detecting 2.3 ppm of C3H6O at 100 °C compared to other binary sensors. As well, the n-p-n In2O3-Co3O4-ZnO ternary sensor presented remarkable sensitivity to the same C3H6O at 150 °C, outperforming other ternary sensors. The n-p In2O3-Co3O4 binary sensor achieved high sensitivity (2.38 ppm-1), a low detection limit (0.142 ppb), and fast response/recovery times (40/43 s) compared to In2O3-CuO, In2O3-Mn3O4, and In2O3-NiO sensors. In contrast, the n-p-n In2O3-Co3O4-ZnO ternary sensor exhibited remarkable sensitivity (0.14 ppm-1), low detection limit (100 ppb), and fast response/recovery times (74/64 s). These exceptional results are attributed to enhanced interfacial synergy, increased oxygen vacancies, and modulation of heterojunction barriers, resulting in improved gas sensing performance. When comparing n-p In2O3-Co3O4 (binary) sensor to the n-p-n In2O3-Co3O4-ZnO (ternary) sensor, the ternary sensor demonstrated improved sensitivity and a lower detection limit. Although operating temperature remains a challenge, these developments have significant improvements in gas-sensing parameters. This highlights the potential for further advancements in ternary sensor technology for real-world applications in air quality monitoring and breath analysis for diabetes detection.