The current study followed green methodology to deliver polymer composites based on methylcellulose (MC) with enhanced optoelectronic properties. Ligands of green tea dye were used successfully to produce zinc metal complexes (Zn-MC). The FTIR established that bands associated with anions of the zinc salt were disappeared in Zn-MC product. The FTIR results of the composite films indicate good interaction among host polymer and the added Zn-MC particles. The XRD pattern revealed the amorphous behavior of the prepared Zn-MC. The humps appeared in the XRD pattern of MC host polymer, dropped in intensity and broadened with increasing Zn-MC concentration. The optical band gap was determined based on UV–vis investigation using various models. The band gap values in all models are close to each other. The optical band gap was found to be 6 eV for pure MC polymer and reduced to 1.6 eV upon adding 36 mL of suspended Zn-MC. Using the Drude-Lorentz oscillator model, specific parameters associated with microscopic properties such as relaxation time (τ), carrier concentration (N/m*), and optical mobility (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq1.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="30" /> </InlineMediaObject> <EquationSource Format="TEX">$\mu_{opt}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>μ</mi> <mrow> <mi mathvariant="italic">opt</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>) were calculated. The parameters determined from the W-D model were used to calculate the optical moments (the M−1 and M−3). The average wavelength of inter-band oscillators (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq2.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">$\lambda_{0}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>λ</mi> <mn>0</mn> </msub> </math></EquationSource> </InlineEquation>), and the average strength of oscillators (<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq3.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">$S_{o}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>S</mi> <mi>o</mi> </msub> </math></EquationSource> </InlineEquation>) were determined with the help of refractive index. It was found that when <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq2.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">$\lambda_{0}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>λ</mi> <mn>0</mn> </msub> </math></EquationSource> </InlineEquation> increases with increasing Zn-MC, it simultaneously causes <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq3.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">$S_{o}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>S</mi> <mi>o</mi> </msub> </math></EquationSource> </InlineEquation> to decrease. The Urbach energy rises with increasing metal complex concentration. The optical conductivity results revealed that increasing of Zn-MC causes a direct increase in optical conductivity. The phase velocity (<InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq6.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">$v_{p}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>v</mi> <mi>p</mi> </msub> </math></EquationSource> </InlineEquation>) and group velocity (<InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq7.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">$v_{g}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>v</mi> <mi>g</mi> </msub> </math></EquationSource> </InlineEquation>) as two key physical parameters related to refractive index were studied. The Magneto-Optical constant known as the Verdet factor (<InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq8.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="40" /> </InlineMediaObject> <EquationSource Format="TEX">$V\left( \lambda \right)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>V</mi> <mfenced close=")" open="("> <mi>λ</mi> </mfenced> </mrow> </math></EquationSource> </InlineEquation>), which characterizes the volume of Faraday rotation per unit of magnetic field and thickness in a single pass was studied. The non-linear refractive index <InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq9.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">$n_{2}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>n</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation> was found to increase in the doped films compared to the clean MC sample. The Kirchhoff functions, which consist of film surface resistance and thermal emission, were determined. The first <InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq10.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="28" /> </InlineMediaObject> <EquationSource Format="TEX">$\chi^{\left( 1 \right)}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>χ</mi> <mfenced close=")" open="("> <mn>1</mn> </mfenced> </msup> </math></EquationSource> </InlineEquation>), and third <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10570_2025_6738_Article_IEq11.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="28" /> </InlineMediaObject> <EquationSource Format="TEX">$\chi^{\left( 3 \right)}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>χ</mi> <mfenced close=")" open="("> <mn>3</mn> </mfenced> </msup> </math></EquationSource> </InlineEquation> order non-linear optical parameters also studied for the MC solid composites. Graphical abstract

Improvement of optoelectronic parameters of methylcellulose (MC) based green polymer composite via zinc metal complexes: structural and optical properties

期刊论文
发表日期：

2025年8月20日

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Dyari M. Mamand,
Sarkawt A. Hussen,
Shujahadeen B. Aziz

摘要

The current study followed green methodology to deliver polymer composites based on methylcellulose (MC) with enhanced optoelectronic properties. Ligands of green tea dye were used successfully to produce zinc metal complexes (Zn-MC). The FTIR established that bands associated with anions of the zinc salt were disappeared in Zn-MC product. The FTIR results of the composite films indicate good interaction among host polymer and the added Zn-MC particles. The XRD pattern revealed the amorphous behavior of the prepared Zn-MC. The humps appeared in the XRD pattern of MC host polymer, dropped in intensity and broadened with increasing Zn-MC concentration. The optical band gap was determined based on UV–vis investigation using various models. The band gap values in all models are close to each other. The optical band gap was found to be 6 eV for pure MC polymer and reduced to 1.6 eV upon adding 36 mL of suspended Zn-MC. Using the Drude-Lorentz oscillator model, specific parameters associated with microscopic properties such as relaxation time (τ), carrier concentration (N/m*), and optical mobility ( $\mu_{opt}$ $μ_{opt}$ ₎ were calculated. The parameters determined from the W-D model were used to calculate the optical moments (the M₋₁ and M₋₃). The average wavelength of inter-band oscillators ( $\lambda_{0}$ $λ_{0}$ ), and the average strength of oscillators ( $S_{o}$ $S_{o}$ ) were determined with the help of refractive index. It was found that when $\lambda_{0}$ $λ_{0}$ increases with increasing Zn-MC, it simultaneously causes $S_{o}$ $S_{o}$ to decrease. The Urbach energy rises with increasing metal complex concentration. The optical conductivity results revealed that increasing of Zn-MC causes a direct increase in optical conductivity. The phase velocity ( $v_{p}$ $v_{p}$ ) and group velocity ( $v_{g}$ $v_{g}$ ) as two key physical parameters related to refractive index were studied. The Magneto-Optical constant known as the Verdet factor ( $V\left( \lambda \right)$ $V (λ)$ ), which characterizes the volume of Faraday rotation per unit of magnetic field and thickness in a single pass was studied. The non-linear refractive index $n_{2}$ $n_{2}$ was found to increase in the doped films compared to the clean MC sample. The Kirchhoff functions, which consist of film surface resistance and thermal emission, were determined. The first $\chi^{\left( 1 \right)}$ $χ^{(1)}$ ), and third $\chi^{\left( 3 \right)}$ $χ^{(3)}$ order non-linear optical parameters also studied for the MC solid composites.

Graphical abstract