In this study, biopolymer composites based on chitosan (CS) with enhanced optical properties were functionalized using Manganese metal complexes and black tea solution dyes. The results indicate that CS with Mn²⁺-complexes can produce polymer hybrids with high absorption, high refractive index and controlled optical band gaps, with a significant reduction from 6.24 eV to 1.21 eV. The refractive index and optical dielectric constant measurements show that the doped CS films have more charge carriers and traps than those in pure CS films. The Lorentz-Drude model was used to derive several significant optical parameters, and the W-D model was utilized to calculate the optical moments M_-1 changing from 0.35 to 2.13 and M_-3 changing from 0.005 to 0.4. It was shown that the doped samples have larger Urbach energy than pure film, increased from 0.29 to 0.55 eV. Tauc and ASF model was also used to calculate the electronic transitions, band structure, and optical characteristics. Bandgap energy based on Tauc model at m = 2, 1/3, 1/2, and 2/3 are 1.77, 1.54, 1.47, and 1.37 eV, based on ASF model are 1.52, 1.42, 1.69, and 1.47 eV, respectively. As a result of changes in the optical diffraction parameters the optical mobility (\({\mu }_{opt}\)) changed from 1.67 to 1.27 and optical resistivity \({\rho }_{opt}\) from 9.36 × 10^–27 to 4.0 × 10^–29. The dopped samples show an increase in their linear optical susceptibility, third-order nonlinear optical susceptibility and nonlinear refractive indices, changing from 3.165 × 10^–15 to 2.831 × 10^–12 esu. Finally, light propagation velocities, surface resistance, and thermal emissivity were also examined.

Confined water inside carbon nanotubes (CNTs) has attracted a lot of attention in recent years, amassing as a result a very large number of dedicated studies, both theoretical and experimental. This exceptional scientific interest can be understood in terms of the exotic properties of nanoconfined water, as well as the vast array of possible applications of CNTs in a wide range of fields stretching from geology to medicine and biology. This review presents an overreaching narrative of the properties of water in CNTs, based mostly on results from systematic nuclear magnetic resonance (NMR) and molecular dynamics (MD) studies, which together allow the untangling and explanation of many seemingly contradictory results present in the literature. Further, we identify still-debatable issues and open problems, as well as avenues for future studies, both theoretical and experimental.

The current research aims to determine the impact of orange peel dye (OPD), an eco-friendly addition, on the optical properties of biodegradable polymers. This study investigates the enhancement of optical properties in solid electrolytes based on chitosan (CS) and glycerol, with varying OPD concentrations. UV–Vis-NIR spectroscopy revealed significantly enhanced UV–visible light absorption in the 200–500 nm region and effective UV light blocking. FTIR analysis showed strong interactions between OPDs and the CS matrix, with functional groups such as O–H, C=O, and C=C. UV–Visible spectroscopy indicated a reduction in the optical band gap from 5.11 eV in pure CS to 2.93 eV and 2.84 eV with increasing OPD concentrations, reflecting alterations in the electronic structure and enhanced sub-bandgap states. The refractive index improved from 1.31 in pure CS to 1.54 and 1.62 in the doped electrolytes, attributed to increased optical density and light-harvesting capability. Optical basicity also increased from 1.01 to 1.32, enhancing donor properties. These results suggest that OPD-doped CS solid electrolytes offer enhanced optical properties, making them suitable for optoelectronic and UV-blocking applications due to their tunable band gap, improved polarizability, and enhanced light interaction.

Natural or synthetic graphite as precursors for the preparation of graphene oxide (GO) have constraints due to their limited availability, high reaction temperature for processing of synthetic graphite and higher generation cost. The use of oxidants, long reaction duration, the generation of toxic gases and residues of inorganic salts, the degree of hazard and low yield are some of the disadvantages of the oxidative-exfoliation methods. Under these circumstances, biomass waste usage as a precursor is a viable alternative. The conversion of biomass into GO by the pyrolysis method is ecofriendly with diverse applications, which partially overcomes the waste disposal problem encountered by the existing methods. In this study, graphene oxide (GO) is prepared from dry leaves of sugarcane plant through a two-step pyrolysis method using ferric (III) citrate as a catalyst, followed by treatment with conc. H₂SO₄. The synthesized GO is analyzed by UV-Vis., FTIR, XRD, SEM, TEM, EDS and Raman spectroscopy. The synthesized GO has many oxygen-containing functional groups (–OH, C–OH, COOH, C–O). It shows a sheet-like structure with a crystalline size of 10.08 nm. The GO has a graphitic structure due to the Raman shift of G (1339 cm⁻¹) and D (1591 cm⁻¹) bands. The prepared GO has multilayers due to the ratio of 0.92 between I_D and I_G. The weight ratios between carbon and oxygen are examined by SEM-EDS and TEM-EDS and found to be 3.35 and 38.11. This study reveals that the conversion of sugarcane dry leaves into the high-value-added material GO becomes realistic and feasible and thus reduces the production cost of GO.

Studying the properties of water confined in carbon nanotubes (CNTs) have gained a lot of interest in recent years due to the vast potential applications of systems in nanoscale liquid transport as well as biology functions. This article presents a comprehensive review of recent experimental and theoretical results using nuclear magnetic resonance (NMR) and molecular dynamics (MD) simulations. Different NMR methods including