Polypyrrole thin films for gas sensors prepared by Matrix-Assisted Pulsed Laser Evaporation technology: Effect of deposition parameters on material properties

Abstract

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.