Carbonized polyvinylidene difluoride films irradiated by variable-energy Ar+: Tunable morphology and resistive sensing

Abstract

In this work, resistive gas sensors based on dehydrohalogenated polyvinylidene difluoride irradiated by variable-energy (500–900 eV) Ar+ ions were investigated. The resulting ion-irradiated polyene-based films were investigated by scanning electron microscopy, energy dispersive x-ray spectroscopy, and Raman spectroscopy. The polyene-based structure was analyzed, and the variation in the films’ morphology, ordering, and graphitization degree with ion energy change was assessed. The resistive sensing response of the obtained composites to ammonia and ethanol was analyzed, revealing the energy- and analyte-dependent shift between positive and negative sensing responses. That allowed us to confirm that the sensing mechanism of the investigated structures is governed by electron or hole transfer induced by the interaction of vapor and the material, which results in various types of responses for the structures with n- and p-type conductivity.