Sensitive Light-Induced Thermoelastic Spectroscopy-Based Oxygen Sensor with a Perovskite-Modified Quartz Tuning Fork

The concentration of oxygen (O2) plays a crucial role in the metabolic respiration, maturation, and ripening processes of fruits. In this study, we propose a novel method for gas detection called light-induced thermoelastic spectroscopy (LITES), which utilizes a quartz tuning fork (QTF) coated with a thin film of CH3NH3PbI3 perovskite. By creating a Schottky junction with silver electrodes on the surface of QTF, the photoelectric and thermoelastic effects were coupled by the CH3NH3PbI3-QTF, thereby enhancing the sensor's detection sensitivity. In addition, encapsulation was taken to ensure the long-Term stability of the CH3NH3PbI3-QTF sensor. We applied the LITES technology to investigate O2 concentration during the storage and decay process of strawberries. By monitoring the fluctuations in O2 concentration, we were able to estimate the degree of strawberry decay. Our findings demonstrate that this low-cost, innovative technique holds promise for replacing conventional photodetectors and has a great potential to apply in studying gas exchange in food packaging and storaging.