Rapid and Selective NH₃ Sensing by Porous CuBr

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Developing sensitive and selective gas sensors for ammonia (NH3) at low concentrations (parts-per-billion) is crucial for environmental monitoring and safety.
• Existing sensors often require high power consumption and heating, limiting their application in portable devices.

Purpose of the Study:

• To develop a room-temperature, solid-state sensor for fast and selective detection of NH3 at ppb levels.
• To investigate the performance of nanostructured porous copper bromide (CuBr) films for NH3 sensing.

Main Methods:

• Fabrication of nanostructured porous CuBr films using flame-aerosol deposition of CuO followed by dry reduction and bromination.
• In situ monitoring of film resistance during fabrication for process control.
• Evaluation of NH3 sensitivity, response time, and selectivity against common interfering gases at various humidity levels.

Main Results:

• Porous CuBr films exhibited an order of magnitude higher NH3 sensitivity and five times faster response times compared to denser films.
• Rapid detection (2.2 min) of NH3 down to 5 ppb was achieved, even at 90% relative humidity.
• Outstanding selectivity (30-260) was demonstrated against common confounders like ethanol, acetone, and CO.

Conclusions:

• The developed room-temperature, solid-state CuBr sensor offers superior performance for NH3 detection, suitable for low-power, portable applications.
• The fabrication process using flame-aerosol technology provides excellent control and opens possibilities for other semiconductor materials.