Enhancement of the structural, optical, and dispersion performance of polyvinyl alcohol via coronene additive for optoelectronic applications

Abstract

Composite films made of polyvinyl alcohol (PVA) filled with various coronene concentrations were fabricated via the solution casting method. Several characterization techniques were used to examine the prepared samples. The x-ray diffraction study shows decreasing semi-crystalline properties in PVA/coronene composites with increasing coronene levels, thereby improving charge carrier mobility and enhancing conductivity. The alterations in the chemical functional groups of the PVA/coronene composites were explored using Fourier-transform infrared spectroscopy (FTIR). The impact of coronene molecules on the optical characteristics of PVA was investigated in the spectral ranges of 190-2500 nm. PVA/coronene composite exhibits higher UV blocking in the 190-400 nm wavelength range, suitable for UV notch filters like laser blocking filters. By increasing the coronene filling ratio from 0 wt% to 3 wt%, both the indirect and direct optical band-gap of PVA films decreased from 5.19 eV and 5.77 eV to 3.85 eV and 5.18 eV, respectively. The single oscillator model (Wemple-DiDomenico) was used to explain the refractive index dispersion region. The extracted values of dispersion energy (Ed), oscillator energy (Eo), dielectric constant at infinite frequency (ε ∞), and lattice dielectric constant (ε L) of PVA/coronene composite samples increased from 0.78 eV, 2.41 eV, 1.32 and 1.41 to 13.44 eV, 12.22 eV 2.10 and 2.13, respectively. These changes in dispersion parameters are due to cross-linking between the PVA polymeric matrix and the coronene. As a result of these improvements, PVA/coronene films could be applied to flexible packaging applications and optoelectronic devices like solar cells or light-emitting diodes.