Preparation And Properties Of Gas Sensitive Sensing Material Based On PEDOT:PSS

In today's world,with the rapid development of industrialization,air pollution is becoming more and more serious.Therefore,it is of great significance to research on gas sensors that can work at room temperature and show high response to low-concentration harmful gases.Poly(3,4-ethylene dioxyethiophene):Poly(styrene sulfonate)(PEDOT:PSS)is one of the most widely used conductive conjugated polymers.Due to its excellent mechanical properties,high conductivity and good film-forming characteristics,it is an ideal material for the preparation of flexible gas sensors.However,pure PEDOT:PSS has low response performance to organic volatile gases,and it is often combined with different nanomaterials such as carbon nanotubes and graphene to improve gas sensitive performance.Although these methods have effectively increased the responsiveness of PEDOT:PSS to organic volatile gases,the response to low-concentration gases is still low,and the selectivity has not been well improved.In this paper,the in-situ polymerization method was used to compound PEDOT:PSS with nanomaterial molybdenum disulfide quantum dots(MoS₂QDs)and porous material ZIF-8,and their morphology and structure were analyzed by SEM,TEM,XRD,and FTIR.Composite materials with high response to acetaldehyde and NH₃were prepared.The specific content can be summarized as follows:(1)PEDOT:PSS/MoS₂QDs based flexible gas sensor was designed and prepared,and its gas sensitivity to acetaldehyde gas was studyed.First,the MoS₂QDs are synthesized by hydrothermal method and the particle size is about 3 nm.A series of PEDOT:PSS/MoS₂QDs nanocomposites were prepared by in-situ polymerization,and the effect of different content of MoS₂QDs on the gas-sensing properties of the composites was studied.The results showed that the gas sensitivity of 21.9%PEDOT:PSS/MoS₂QDs composite was the best,and the response value was as high as 15 for acetaldehyde gas at a concentration of 10 ppm.Compared with pure PEDOT:PSS,the response value is significantly higher.Further research found that the PEDOT:PSS/MoS₂QDs composite material showed excellent selectivity,repeatability and long-term stability for the detection of acetaldehyde gas.(2)The PEDOT:PSS/ZIF-8 based flexible gas sensor was designed and prepared,and its gas sensitivity to NH₃was studied.It can be seen from the SEM and TEM images that the ZIF-8 nanoparticles are stacked together and the particle size is uniform.A series of PEDOT:PSS/ZIF-8 nanocomposites were prepared by in-situ polymerization.The effect of different content of ZIF-8 on the gas-sensitive properties of the composites was studied.The results showed that the gas sensitivity of 17.4%PEDOT:PSS/ZIF-8 composite was the best,and the response value was as high as 14for NH₃at a concentration of 10 ppm.Compared with pure PEDOT:PSS,the response value is significantly higher.The gas sensitivity of PEDOT:PSS/ZIF-8 composite to various gases is also studied in this paper.The results show that the composites have high selectivity and long-term stability to NH₃.