Temperature dependent dielectric properties of self-standing and flexible poly(vinylidene fluoride) films infused with Er3+ doped GeO2 and SiO2 nanoparticles

摘要

The synthesis of Er3+@GeO2 and Er3+@SiO2 nanoparticle impregnated self-standing poly(vinylidene fluoride) films by a facile solution casting technique has been reported. The prepared films were thoroughly characterized using X-ray diffraction technique, field emission scanning electron microscopy, and transmission electron microscopy. The optical properties were evaluated using UV-Vis spectroscopy. Detailed study on the temperature dependent dielectric properties of the composite films with different Er3+ content were also investigated to establish the electrical properties of the same, which revealed the presence of different relaxation processes, namely, alpha(c) and rho. Due to the smaller size, Er3+@SiO2 was found to disperse better in the PVDF matrix than Er3+@GeO2, which resulted in higher dielectric constant of the former at 300 K. At higher temperature (403 K), the behavior was reversed due to the formation of larger sized low mobility complexes. An investigation on ac conductivity proved the conduction mechanism for neat as well as composite PVDF films to follow the Correlated Barrier Hopping model. The loading of Er3+@GeO2 and Er3+@SiO2 nanoparticles in the PVDF matrix significantly enhances the dielectric properties without losing the flexibility of the composite films. (C) 2016 Wiley Periodicals, Inc.