Abstract
In this work, a green approach was implemented to prepare polymer composites using polyvinyl alcohol polymer and the extract of black tea leaves (polyphenols) in a complex form with Co2+ ions. A range of techniques was used to characterize the Co2+ complex and polymer composite, such as Ultraviolet–visible (UV-Visible) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The optical parameters of absorption edge, refractive index (n), dielectric properties including real and imaginary parts (εr, and εi) were also investigated. The FRIR and XRD spectra were used to examine the compatibility between the PVA polymer and Co2+-polyphenol complex. The extent of interaction was evidenced from the shifts and change in the intensity of the peaks. The relatively wide amorphous phase in PVA polymer increased upon insertion of the Co2+-polyphenol complex. The amorphous character of the Co2+ complex was emphasized with the appearance of a hump in the XRD pattern. From UV-Visible spectroscopy, the optical properties, such as absorption edge, refractive index (n), (εr), (εi), and bandgap energy (Eg) of parent PVA and composite films were specified. The Eg of PVA was lowered from 5.8 to 1.82 eV upon addition of 45 mL of Co2+-polyphenol complex. The N/m* was calculated from the optical dielectric function. Ultimately, various types of electronic transitions within the polymer composites were specified using Tauc’s method. The direct bandgap (DBG) treatment of polymer composites with a developed amorphous phase is fundamental for commercialization in optoelectronic devices.
Highlights
The utilization of polymer materials instead of metallic ones has become more widespread in recent years [1]
In the extraction process, distilled water was used as a solvent for extracting the tea leaf components; 50 g of black tea leaf was added to 250 mL distilled water, maintained at a temperature at 90 ◦C and kept away from sunlight
The X-ray diffraction patterns for the pure polyvinyl alcohol (PVA) and composite films were obtained at room temperature, using a Bruker AXS with a working voltage and current of 40 kV and 45 mA, respectively
Summary
The utilization of polymer materials instead of metallic ones has become more widespread in recent years [1] This is due to the structural characteristics of the former, such as the tunability of optical bandgaps [2]. Especially inorganic, nanocomposite ones, can be fabricated by incorporating inorganic nanoparticles that are used in optoelectronic systems [3], making it possible manipulate their optical properties [4]. It is of great importance to modify PVA by narrowing the bandgap polymer by metal complex incorporation. This opens a new perspective for research in optical materials and developing optoelectronic and photonic devices. The green methodology and desired optical properties, notably, the small Eg of the polymer composite, indicate the significance of the present study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
