Developing thermally stable CuO/DPC/PVC nanocomposite films for flexible UV shielding and dielectric applications

This work focuses on developing novel organic nanocomposites (ONCs) for optoelectronic devices and UV and blue light shielding applications. Films of polyvinyl chloride (PVC) modified with diphenyl carbazide (DPC) and CuO nanoparticles (NPs) were prepared by a solution-casting approach. The structure and chemical composition of the films were checked by X-ray diffraction, ATR/Fourier transform-infrared (FT-IR) spectroscopy, FE-SEM, and EDX. The CuO and DPC increased the amorphous nature of the films, and the complexation among the functional groups of PVC, DPC, and CuO was observed in the FT-IR spectra. The uniform distribution of all elements was confirmed by EDX and mapping analyses. TGA and DSC (thermal) analyses showed that the films’ thermal stability, melting, and decomposition temperatures are significantly modified upon CuO and DPC addition. UV–vis spectroscopy revealed that the addition of CuO and DPC is essential for PVC to block the UV and blue light. The PVC’s direct bandgap structure can be tuned from 5.15 to 3.0 eV for direct transitions and from 4.9 to 2.4 eV for indirect ones. The values of PVC’s optical parameters depend on DPC/CuO addition. The relative dielectric constant and electric conductivity were improved significantly by these additives. The study of dielectric modulus and the Cole-Cole diagram revealed that the conduction in these films does not obey the Debye model. The significant improvements in the structural features, thermal and optical parameters, dielectric properties, and conductivity indicate that the prepared ONC films are the best candidates for dielectric and optoelectronic applications and utilizations where UV/blue light shielding and thermal stability are required.