Multiplex-gas detection based on non-dispersive infrared technique: A review

Compared to the gas sensors of electrochemical and semiconductors, the non-dispersive infrared technique (NDIR) can selectively detect multiple types of gases due to the 'fingerprinting' characteristic by the specificallyabsorbed spectrum. However, the mass types of the gases have cross-talk over a limited bandwidth, as well as the inevitable interference from humidity during the measurement. Further progress in infrared intensity, optical path design, signal-to-noise ratio, system structure, integration, etc. is required for high-precision detection of single or multiple gases. In this article, we review the state of the art of the solutions for multiple gas detection realized by NDIR. The most commonly used gas absorption peaks distributed in the mid-infrared spectra are summarized, including atmospheric contaminants, toxic, flammable, and explosive gas samples. Besides, recent studies on improving detection performance and sensor system integration are also discussed.