Polycrystalline In₂O₃ modified with CdIn₂S₄ for enhanced triethylamine gas detection.

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Development of selective and sensitive gas sensors is critical for environmental monitoring.
• Indium oxide (In2O3) based materials show promise but often lack selectivity and speed.
• Heterojunction engineering offers a pathway to enhance material properties.

Purpose of the Study:

• To create a novel low-power, highly selective triethylamine (TEA) gas-sensitive material.
• To investigate the gas sensing performance of a CdIn2S4-In2O3 heterojunction.
• To understand the structure-property relationships governing TEA detection.

Main Methods:

• Fabrication of a hierarchical mixed-phase In2O3 structure.
• Formation of a CdIn2S4-In2O3 heterojunction by integrating CdIn2S4 rich in cationic acid sites.
• Gas sensitivity tests were conducted to evaluate response/recovery speed, response value, and detection limits.

Main Results:

• The CdIn2S4-In2O3 sensor exhibited a faster response/recovery speed (1 s/88 s) compared to unmodified In2O3.
• A significantly enhanced response value (29.8 to 10 ppm TEA at 60°C) was observed, 2.9 times that of In2O3.
• The sensor achieved a low detection limit in the ppb level (100 ppb with SNR of 3.2).

Conclusions:

• The hierarchical heterostructure, combining 2D materials and layered structures, enhances response sites and molecule adsorption/desorption.
• Interfacial electrical modulation and synergistic effects from CdIn2S4's acidic sites improve TEA adsorption and selective recognition.
• The developed sensor demonstrates excellent sensitivity and selectivity for triethylamine detection.