Methane Gas Detection System With Integrated Infrared Perovskite Detecto

Perovskite（PVK）semiconductors have been hailed as potential candidates at the forefront of optoelectronic gas sensing applications due to their solution processability and excellent sensitivity.Photoelectric gas sensors based on PVK have good application prospects in future trace gas sensing applications,such as industrial control,environmental monitoring,and agricultural production.Using PVK as a carrier,most photoelectric detectors can detect can detect photoelectric signals in ultraviolet bands and visible optical wave sections.However,the absorption peaks of gases such as methane（1653 nm）,ammonia（1512 nm）,and carbon monoxide（1565 nm）are all in the infrared region.Against this background,this paper prepared CH₃NH₃Pb I₃ composite doped Pb Se material as the light absorption layer,using nano-columnar structure CH₃NH₃Pb I₃,which enhanced light absorption and photocarrier generation and obtained infrared perovskite（IR-PVK）gas photodetector with good characteristics in the infrared region.A trace methane gas test system was designed and built with infrared absorption spectroscopy and IR-PVK photodetector.This paper mainly has the following aspects of work:（1）Designed and prepared a nano-columnar structure PVK photoelectric gas detector and used the finite element method to simulate and study the carrier density and distribution inside the device.The effect of PVK nanopillar structures with different particle sizes on the change of carrier concentration was simulated.The PVK device with a particle size of 100 nm was identified as the best-performing device.The nanocolumnar IR-PVK was prepared by doping Pb Se material by an anodic alumina process,improving the photoelectron collection efficiency and broadening the absorption range.Graphene ring electrodes were prepared,and the potential barrier between graphene and PVK could rectify the device.（2）The photoelectric performance of the IR-PVK photoelectric gas detector was tested.Periodic PVK nanorods can enhance light absorption in the infrared region,distributed electromagnetic field,and collection of photogenerated carriers.Due to the quantum confinement effect of nanorods,nanostructured devices can achieve higher responsivity.Compared with traditional In Ga As and Pb Se sensors（responsivity less than 1 A/W,detection degree 10⁸-10⁹ Jones）,the power consumption（1.5μW）,detectivity(1.138×10¹¹ Jones),and responsivity（18 A/W）of the nanocolumnar IR-PVK device with a diameter of 100 nm are better（incident light 1653 nm）.（3）A detection system for trace methane gas was built with an IR-PVK photodetector as the core of fast light sensing.IR-PVK detectors can adapt to the high-frequency response requirements of tunable laser absorption spectroscopy-wavelength modulation spectroscopy（TDLAS-WMS）technology.An as-fabricated IR-PVK photodetector with trans-impedance amplifier circuits can be compatible with the designed high-precision TDLAS gas sensing system.A digital quadrature lock-in amplifier was used to demodulate the second harmonic（2f）signal of the TDLAS gas sensing circuit.After many experiments,it showed that the IR-PVK device with a particle size of 100 nm had a high detection rate(1.138×10¹¹ Jones),and the device achieved a fast response to functional infrared light（37μs）.The gas test system with a high signal-to-noise ratio（2800）.In the range of 100 ppb～2000 ppm,there is an excellent linear relationship between the second harmonic signal’s amplitude and the methane gas concentration.The lowest detection limit（LOD）of CH₄ can reach up to 100 ppb,and the response time to the CH₄ gas’s exposure is as low as 3 s for this laser-based gas-sensing system.