Polypyrrole Thin Films For Gas Sensors Prepared By Matrix-assisted Pulsed Laser Evaporation Technology: Effect Of Deposition Parameters On Material Properties

摘要

Thin films of polypyrrole (PPY) were prepared by Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technology from two matrices: water and dimethylsulfoxide (DMSO). The deposition was carried out using a KrF excimer laser (laser fluence F ranged from 0.1 to 0.6 J cm~(-2)). This work deals with optimization of two deposition parameters - laser fluence and number of pulses - for both matrices. From the deposition curves, the fluence thresholds, F_(th), and maximum growth rates were subsequently determined (water matrix: F_(th)-0.40-0.45 J cm~(-2), maximum growth rate 0.16 nm pulse~(-1); DMSO matrix: F_(th)～0.25-0,30 J cm~(-2); maximum growth rate 0.20 nm pulse~(-1)). The changes in chemical composition of deposited layers were studied by Attenuated Total Reflection Fourier Transform Infrared spectroscopy. Surface morphology was characterized by Atomic Force Microscopy. A discussion is also presented concerning relationships between laser fluence and chemical composition of deposited layers with respect to their potential application in gas sensors. Finally, the response of a sensor with a MAPLE deposited PPY active layer to air humidity is presented.