Fully environmental approach to design advanced optical polymer composites with high optoelectronic performance using green synthesized nickel metal complexes

Sep 30, 2026

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Breakthrough methodology is used to fabricate PVA-based polymer composite films via a simple casting route, integrating green-synthesized nickel metal complexes (NiMC). Structural and optical properties are evaluated using XRD, FTIR, and UV-Vis, showing strong interaction between NiMC and PVA functional groups through FTIR band shifts and peak broadening. FESEM analysis assesses roughness and phase separation, while multiple optical models extract direct and indirect optical band gaps. A full set of optoelectronic parameters—dielectric constants, loss functions, susceptibilities, nonlinear refractive index, skin depth, oscillator strengths, and interband transition photon energies—are quantified to characterize electron-transfer capability from HOMO to LOMO orbitals.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages31

Reading Time1 h 18 min

AccessFree to download

Introduction

Green tea polyphenols, catechins, and formation of metal complexes

Coordination chemistry background for transition-metal complexes

Materials and Methods

Preparation via casting of PVA with green-synthesized NiMC

Characterization using XRD, FTIR, UV-Vis, and FESEM

Optical and Optoelectronic Analysis

Band gap extraction and related optical parameters

Dielectric, loss functions, and nonlinear optical properties

Oscillator model parameters and photon-to-electron transfer study

[www. nature.com/scientificreports](www. nature.com/scientificreports) OPEN Fully environmental approach to design advanced optical polymer composites with high optoelectronic performance using green synthesized nickel metal complexes Dana S. Muhammad1,2, Dara M. Aziz3􀀍 & Shujahadeen B. Aziz4􀀍 In this study breakthrough methodology has been used to deliver advanced polymer composites based on polyvinyl alcohol (PVA) integrated with green-synthesized nickel metal complex (NiMC), utilizing a simple casting methodology. The structural and optical characteristics of PVA composite films were studied using XRD, FTIR, and UV-Vis spectroscopy, respectively. Band shifting in FTIR spectra and broadening of sharp peak in PVA composites compared to pure PVA establish strong interaction between NiMC and PVA functional groups. The surface of the films was examined for roughness and phase separation using FESEM investigation. Various optical models were employed to determine the optical band gap (Eg). The Eg decreased from 6.05 eV to 1.69 eV for direct and 1.21 eV for indirect transitions. The increase in Urbach energy from 0.28 to 0.62 eV was correlated with XRD results. The oscillator energy parameters were determined from the empirical Wemple-DiDomenico model. The real and imaginary dielectric constants, volume and surface energy loss functions, optical density, 3rd order susceptibility X(3), nonlinear refractive index n(2) and skin depth was studied in detail. Optical oscillator strengths(f), optical moments M− 1 and, and interband strength M− 3 were also determined. The ( J) and figure of merit (φ) versus hv were used to specify the photons that are capable to electron transfer from HOMO to LOMO orbitals. The optoelectronic parameters, including (N/M*), t,(wp ),(uopt ),(Popt ), the average interband oscillator wavelength, and average oscillator strength(So), were also determined for all the films. Keywords PVA polymer composite, Green tea dye ligand, Coordination chemistry & metal complexes, XRD&FTIR study, Optoelectronic studies Metal complexes have been used for diverse applications for ages, with initial instances observable to ancient civilizations. The systematic investigation and utilization of metal complexes in chemistry, especially in coordination chemistry was originated in the late 19th and early 20th centuries1. Consequently, researchers and scientists are developing novel, environmentally friendly, and cost-effective materials2. The leaves of green tea after processing and preparation contain tea polyphenols, amino acids, caffeine, tannins, and saponins that comprises around [10–30%(w/w)] polyphenols and [2–4%(w/w)] caffeine. Catechins are polyhydroxy compounds that form the principal polyphenolic category in tea products. [epicatechin gallate (ECG), Epigallocatechin gallate (EGCG), epicatechin (EC), and epigallocatechin (EGC)] are the four primary catechins present in fresh green tea leaves, each displaying unique biological effects3,4. Previous studies established the formation of complexes between Zn²⁺ and Co²⁺ transition metal ions and phenolic chemicals from the high-weight molecular fraction 1Department of Physics, College of Education, University of Sulaimaniyah, Old Campus, Sulaymaniyah 46001, Iraq. 2Department of Physics, College of Science, University of Sulaimaniyah, New Campus, Qlysan Street, Sulaymaniyah 46001, Iraq. 3Department of Chemistry, College of Science, University of Raparin, Ranya 46012, Iraq. 4Turning Trash to Treasure Laboratory (TTTL), Research and Development Center, University of Sulaimani, New Campus, Qlyasan Street, Sulaymaniyah 46001, Iraq. 􀀍 email: [darachem@uor.edu.krd](darachem@uor.edu.krd); [shujahadeenaziz@gmail.com](shujahadeenaziz@gmail.com) [www. nature.com/scientificreports/](www. nature.com/scientificreports/) obtained from green tea. Interactions between polyphenols and metal ions could impact the transfer of these metal ions and (GTD) polyphenols to metal comple

FAQs

How are PVA composite films prepared in the study?

PVA is integrated with green-synthesized nickel metal complexes (NiMC) using a simple casting methodology to form composite films.

Which techniques are used to study the structural and optical behavior?

XRD and FTIR are used for structural and interaction analysis, while UV-Vis spectroscopy is used for optical characterization; FESEM is used to examine surface roughness and phase separation.

What changes are observed in optical band gap values and what do they indicate?

The optical band gap decreases from 6.05 eV to 1.69 eV for direct and to 1.21 eV for indirect transitions, indicating modified optical transitions in the PVA–NiMC composites and supporting stronger interfacial interactions.

Sep 30, 2026

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