Infrared Trace Gas Sensing With a Fast Perovskite Nano-Structure Laser Photodetector

In the present work, we firstly demonstrated infrared perovskite nanorods as a state-of-the-art fast photo-sensing core so that they could adapt to the demand of infrared trace gas sensing. Periodic perovskite nanorods can enhance light absorption in the infrared regime, boost the distributed electromagnetic field, and benefit the collection of photo-generated carriers. An as-fabricated photodetector (18 A/W) with trans-impedance amplifier circuits can be compatible with the designed high-precision tunable diode laser absorption spectroscopy (TDLAS) gas sensing system. A digital quadrature phase-locked-loop amplifier is used to demodulate the second harmonic (2f) signal for the TDLAS gas sensing circuit, where the circuit exhibits a high detectivity ( $1.138\times 10^{11}$ Jones) and 2800 signal-to-noise ratio (SNR). A good linear relationship is observed between the amplitude of the 2f signal and the CH4 concentration in the range from 100 ppb to 2000 ppm. Our perovskite-based gas-sensing system is quite promising for future infrared trace gas sensing applications, such as medical expiratory gas sensors and greenhouse gas monitoring.