Highly sensitive light-induced thermoelastic spectroscopy oxygen sensor with co-coupling photoelectric and...

A light-induced thermoelastic spectroscopy (LITES) gas detection method based on CH₃NH₃PbI₃ perovskite-coated quartz tuning fork (QTF) was proposed. By coating CH₃NH₃PbI₃ thin film on the surface of ordinary QTF, a Schottky junction with silver electrodes was formed. The co-coupling of photoelectric effect and thermoelastic effect of CH₃NH₃PbI₃-QTF results in a significant improvement in detection performance. The oxygen (O₂) was select as the target analyte for measurement, and experimental results show that compared with the commercial standard QTF, the introduction of CH₃NH₃PbI₃ perovskite Schottky junction increases the 2f signal amplitude and signal-to-noise ratio (SNR) by ∼106 times and ∼114 times, respectively. The minimum detection limit (MDL) of this LITES system is 260 ppm, and the corresponding normalized noise equivalent absorption coefficient (NNEA) is 9.21 × 10^-13 cm^-1·W·Hz^-1/2. The Allan analysis of variance results indicate that when the average time is 564 s, the detection sensitivity can reach 83 ppm. This is the first time that QTF resonance detection has been combined with perovskite Schottky junctions for highly sensitive optical gas detection.