Self-powered Ammonia Sensor Based On Polyaniline

Self-powered system is a new kind of integrated system which can harvest energy from the environment and transform it into electrical,which could be used to power the functional devices in the system without external power source.Accordingly,it has attractive application prospects in biomedicine,environmental monitoring,military reconnaissance and safety protection alarm.In this thesis,we focus on the self-powered ammonia sensor and successfully fabricate a self-powered ammonia sensor based on polyaniline(PANI)with a lead zirconate titanate(PZT)based piezoelectric nanogenerator powering it.PANI has been widely used in gas sensors because of its special doping mechanism,excellent conductivity,and environmental stability.In our work,the intrinsic state PANI is prepared by chemical polymerization and doped with proton acid HCl.The eigenvalue PANI exists in the form of irregular aggregates,and large gaps exist between the stacked aggregates.After HCl doping which mainly occurs on quinone nitrogen atoms,the gaps between aggregates become smaller which leads to a certain crystallinity for the aggregates.Subsequently,we use the doped PANI to fabricate ammonia sensor,and test its sensitivity towards gases at room temperature.Its sensitivity increases with the increase of ammonia concentration and have a good selectivity for ammonia.PZT piezoelectric ceramics have excellent piezoelectric properties,which paves the way to fabricate piezoelectric nanogenerators with high output.In our work,the aligned PZT nanowires are prepared by electrospinning and calcination process.They were fixed on flexible substrates and made into PZT piezoelectric nanogenerators.It is determined that the output signal is a real piezoelectric signal through the polarization reversal experiment.When the driving frequency is 5 Hz,the output of the generator is about 0.15 V,and the output of the current is about 1.5 nA.The PZT piezoelectric nanogenerator and PANI gas sensor are combined to fabricate a selfpowered gas sensor.The sensor can achieve the monitoring of different concentrations of ammonia,whose current output increases with the increase of ammonia concentration.