Design, Preparation And Application Of Perovskite Gas Sensor For Room Temperature NO₂ Detectio

In modern society,environmental problems are the focus of human society.The gas pollutants in the environment threaten human health seriously.Among them,vehicle and boiler emissions contain a large amount of NO₂,which will damage the human respiratory system and even endanger life safety.Therefore,whether from the perspective of environmental protection or human health,it is of great significance to realize the high-sensitivity detection of NO₂.At present,metal oxide gas sensors are mainly used to detect NO₂ with high sensitivity,but their detection is generally worked at high-temperature environment.The detection sensitivity of room-temperature and low-temperature is low,which seriously hinders its practical application and development.Therefore,it is meaningful to develop sensing materials with high sensitivity and recyclable for NO₂ detection at room temperature.Based on the development of halide perovskite gas sensors with high sensitivity response to NO₂ at room temperature,we designed and prepared organic-inorganic hybrid perovskite thin film gas sensors with different microstructure by one-step spin coating method in air atmosphere and using ethyl acetate as anti-solvent through material component adjustment and surface interface state modification of different molecules.The detection performance of NO₂ gas at room temperature under different environments such as light,darkness and ultraviolet irradiation was explored and discussed.The following research work has been carried out:1.FA_0.83Cs_0.17PbI₃ perovskite films（FACs）were prepared on the surface of interdigital electrode by one-step spin coating method in air atmosphere and treated with ethyl acetate（EA）anti-solvent.FACs gas sensor was constructed and used for detecting NO₂ gas at room temperature.The results show that the prepared FACs perovskite exposes multiple oriented crystal planes and increases the interaction with gas molecules.The device has high response(R_{10 ppm NO2}=2.0),superfast response time(t_res=2 s)and recovery time(t_rec=20 s),low limit detection concentration（LOD=140 ppb）,selectivity and good stability.In addition,FACs gas sensor shows good response and stability to NO₂ gas at room temperature under different illumination such as darkness and ultraviolet light,which increases the service conditions of FACs gas sensor.This work opens up a new way for high sensitivity detection of NO₂ at room temperature.2.Based on the stability of perovskite films,the 3D FACs perovskite films were modified by Pyrrolidine Hydriodide（Py I）.In the air atmosphere,the surface of FACs film was covered with Py Pb I₃ by spin-coating method.The 1D/3D perovskite films(Py Pb I₃/FA_0.83Cs_0.17Pb I₃)were successfully constructed.The 1D/3D perovskite films showed a good response to NO₂ gas at room temperature,a detection limit as low as100 ppb,good reversibility and selectivity.More importantly,compared with FACs sensors,the stability of 1D/3D perovskite sensors has been significantly improved.In the air,there is almost no significant attenuation of response,only from 1.74 to 1.68.At the same time,the 1D/3D perovskite sensor also shows short response time/recovery time for NO₂ under UV irradiation and dark conditions.Therefore,the sensor based on 1D/3D perovskite greatly improves the stability of FACs perovskite devices in detecting NO₂ at room temperature,which provides the possibility for further practical application.