Self-Powered, Photovoltaic-Driven NH₃ Sensor: Ultra-High Selectivity, High Sensitivity, and IoT-Enabled Real-Time...

Area of Science:

• Materials Science
• Chemical Sensing
• Semiconductor Devices

Background:

• Ammonia (NH₃) detection is crucial for environmental, industrial, and food safety applications.
• Conventional sensors often require external power, hindering efficiency and portability.
• Developing self-powered gas sensors is a key challenge in modern technology.

Purpose of the Study:

• To develop a novel self-powered ammonia sensor.
• To integrate photovoltaic effects with gas sensing for energy-efficient operation.
• To demonstrate the sensor's performance and potential for real-world applications.

Main Methods:

• Fabrication of a silicon corrole-functionalized TiZnN₂ (SipC-TiZnN)/p-Si heterostructure.
• Utilizing the photovoltaic effect of the TiZnN₂/p-Si junction for charge separation under visible light.
• Performance evaluation including sensitivity, selectivity, stability, and humidity resistance.
• Computational analysis using Density Functional Theory (DFT) and Scanning Kelvin Probe (SKP) measurements.

Main Results:

• The sensor demonstrated high ammonia sensitivity (2.62 × 10⁻⁴ ppm⁻¹) and an ultra-low detection limit of 0.9 ppm.
• Excellent selectivity for NH₃ over other common gases was observed.
• The device maintained stability for over 90 days and operated reliably under high humidity (≈75% RH).
• DFT and SKP confirmed strong NH₃ adsorption on the sensor surface.

Conclusions:

• The novel SipC-TiZnN/p-Si heterostructure enables efficient, self-powered ammonia sensing.
• The sensor's high performance and stability make it suitable for real-world applications.
• A portable, IoT-enabled prototype successfully monitored fish freshness, showcasing practical utility.