Simple Thermal Annealing-Assisted Direct Synthesis and Optical Property Study of CuO Nanoparticles Incorporated Polyvinyl Alcohol Films

This article reports a simple thermal annealing-assisted direct synthesis method to prepare copper oxide (CuO) nanoparticles incorporated in polyvinyl alcohol (PVA) films and a systematic study of their optical properties. CuO-PVA nanocomposite films are prepared with a different weight percentage of CuO in the PVA matrix. Scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible spectroscopy, and photoluminescence spectroscopy are employed to study the prepared films. XRD confirms the formation of crystalline CuO nanoparticles in PVA, while the SEM analysis shows uniformly distributed spherical nanoparticles in PVA. The findings show that thermal annealing at a mild temperature plays a crucial role in improving the crystallinity and optical properties of the nanocomposite film. In comparison to PVA, CuO-PVA nanocomposite exhibits improved absorption with a new absorption band in the lower wavelength region. The nanocomposite samples excited with 300 nm show intense photoluminescence (PL) at 365 nm and an increase of PL intensity with CuO concentration in the PVA matrix. In contrast, samples excited with 425 nm show green emission at 550 nm in the visible region of the electromagnetic spectrum. The PL in CuO-PVA nanocomposites can be originated due to the transitions associated with acceptor and donor defects in the material. The study opens up a new route to fabricate CuO-PVA nanocomposites with superior optical properties.