Tunable photoluminescence emissions and large dielectric constant of the electroactive poly(vinylidene fluoride-hexafluoropropylene) thin films modified with SnO2 nanoparticles

In the present study, SnO2 nanoparticles (NPs) have been synthesized hydrothermally at 100 degrees C and 150 degrees C. The NPs have been characterized by X-ray diffraction (XRD), UV-visible spectroscopy and field emission scanning electron microscopy (FESEM). Thereafter, poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) with different contents (1-15 wt%) of SnO2 NPs has been synthesized by a simple solution-casting method. An electroactive beta-phase formation mechanism in the NP-incorporated PVDF-HFP thin films is confirmed by XRD, Fourier transform infrared spectroscopy and differential scanning calorimetry. FESEM images show interfacial interaction in the thin films between the polymer matrix and the NPs. Maximum b-phase nucleation of similar to 74% has been reached by 10 wt% addition of SnO2 NPs synthesized hydrothermally at 100 degrees C. The photoluminescence emission spectra show two UV and visible emissions at two excitation wavelengths. Uniform distribution of the NPs in the polymer matrix leads to large dielectric constant similar to 2578.44 at 20 Hz due to addition of 10 wt% SnO2 NPs (100SO) in PVDF-HFP matrix. The large increase in dielectric constant has been successfully explained in terms of MWS polarization effect and percolation theory.