In this work solid composite films of polymer-metal complexes based on methyl cellulose (MC) and lead-metal complex (Pb2+-MC) were fabricated using green approach. The functional group of polyphenols in green tea (GT)-dye confirmed by FTIR investigation are crucial to capture the Pb2+ heavy ion and transforming it to Pb2+-MC. The reduction in crystallinity was confirmed throughout the XRD investigation. The optical properties of the composite films were examined using UV-vis method. Increased refractive index and optical dielectric properties ascribed to tremendous Pb2+-complexes in the MC: Pb-MC composite films. Drude-Lorentz classical model and Taucs approach were used to study the localized density of states (N/m*) and energy band gap (Eg). The increase in Urbach energy from 0.93 to 1.57 at 36% doping confirms the increase in amorphousness phase. Moreover, sheet resistance (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\:{R}_{S}\)</EquationSource> </InlineEquation>) and thermal emissivity (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\:{E}_{th}\)</EquationSource> </InlineEquation>) were determined from refractive index and transmittance parameters. The phase velocity (νp) is more dropped in the composite films compared to group velocity(νg). The relaxation time (τ) of the film with minimum energy band gap was located at the lowest photon energy. We measured the nonlinear refractive index (n₂), the third-order nonlinear susceptibility <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\:\left({\chi\:}^{\left(3\right)}\right)\)</EquationSource> </InlineEquation>,, and the linear optical susceptibility <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\:\left({\chi\:}^{\left(1\right)}\right)\)</EquationSource> </InlineEquation> for every film. The results for pure MC were <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\:\left({\chi\:}^{\left(3\right)}\right)\)</EquationSource> </InlineEquation>, = 6.09 × 10⁻¹¹ esu, <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\:\left({\chi\:}^{\left(1\right)}\right)\)</EquationSource> </InlineEquation>, = 0.773, and <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\:{n}_{2}\)</EquationSource> </InlineEquation> = 2.006 × 10⁻⁴ cm²/W. It is worth noting that these parameters showed a notable improvement in linear and nonlinear optical characteristics when 36 mL of the Pb-MC was added, rising to 4.52 × 10⁻⁸ esu, 4.038, and 1.054 × 10⁻⁶ cm²/W, respectively.

Green synthesized metal complex as a novel approach to replace conventional ceramic fillers for polymer composite fabrication with desired optoelectronic properties: study of electron interband transition using UV-vis spectroscopic approach

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发表日期：

2025年11月27日

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

摘要

In this work solid composite films of polymer-metal complexes based on methyl cellulose (MC) and lead-metal complex (Pb²⁺-MC) were fabricated using green approach. The functional group of polyphenols in green tea (GT)-dye confirmed by FTIR investigation are crucial to capture the Pb²⁺ heavy ion and transforming it to Pb²⁺-MC. The reduction in crystallinity was confirmed throughout the XRD investigation. The optical properties of the composite films were examined using UV-vis method. Increased refractive index and optical dielectric properties ascribed to tremendous Pb²⁺-complexes in the MC: Pb-MC composite films. Drude-Lorentz classical model and Taucs approach were used to study the localized density of states (N/m*) and energy band gap (E_g). The increase in Urbach energy from 0.93 to 1.57 at 36% doping confirms the increase in amorphousness phase. Moreover, sheet resistance ( \(\:{R}_{S}\) ) and thermal emissivity ( \(\:{E}_{th}\) ) were determined from refractive index and transmittance parameters. The phase velocity (ν_p) is more dropped in the composite films compared to group velocity(ν_g). The relaxation time (τ) of the film with minimum energy band gap was located at the lowest photon energy. We measured the nonlinear refractive index (n₂), the third-order nonlinear susceptibility \(\:\left({\chi\:}^{\left(3\right)}\right)\) ,, and the linear optical susceptibility \(\:\left({\chi\:}^{\left(1\right)}\right)\) for every film. The results for pure MC were \(\:\left({\chi\:}^{\left(3\right)}\right)\) , = 6.09 × 10⁻¹¹ esu, \(\:\left({\chi\:}^{\left(1\right)}\right)\) , = 0.773, and \(\:{n}_{2}\) = 2.006 × 10⁻⁴ cm²/W. It is worth noting that these parameters showed a notable improvement in linear and nonlinear optical characteristics when 36 mL of the Pb-MC was added, rising to 4.52 × 10⁻⁸ esu, 4.038, and 1.054 × 10⁻⁶ cm²/W, respectively.