摘要
In this paper,bottom contact organic thin-film transistor(OTFT)gas sensors were prepared.Silicon dioxide(SiO2)and titanium/aurum(Ti/Au)were used as the insulating layer and the electrode for the device,respectively.The multi-walled carbon nanotubes(MWCNTs)/α-sexithiophene(α-6T)bilayer films were used as the active layer,andα-6T single layer sensitive film was also prepared for comparison purpose.The electrical and trace NO2-sening properties of these two OTFT gas sensors were tested and analyzed.The results showed that,the OTFT device based on MWCNTs/α-6T bilayer had obviously better electrical properties,better stabilities and higher NO2-sening response values than the device withα-6T single layer,in which both the carrier mobility(μ)and on/off current ratio enhanced two order of magnitude.The improved performance of bilayer OTFT can be explained that MWCNTs acted as highly conducting bridges connecting the crystalline terraces in theα-6T film.Threshold voltage(VT),carrier mobility,on/off current ratio and grid current which showed extremely similar variation trend as source-drain current,were optional parameters to reveal the gas-sensing characteristic of OTFT gas sensors.Morphology analysis showed that the special feature of MWCNTs had certain influence on the gas-sensing properties.
基金
supported by the Natural Natural Science Foundation of China(Grant Nos.61176066,61101031)
