The Role of Acid Concentration on Band Gap Shrinkage in Cellulose Nanocrystals Fabricated from Water Hyacinth

In this study, the fingerprint of the acid concentration during the hydrolysis process on the optical band gap of cellulose nanocrystals (CNCs) has been systematically studied. The CNCs have been prepared using hydrochloric acid at a hydrolysis temperature of 50°C and at a constant hydrolysis time of 4 hours but with varying hydrochloric cid concentrations of 5%, 10% and 15%. The crystalline structure and phase identification of the CNCs have been studied using XRD technique. UV-Vis Spectroscopy has been done and the optical band gap energy calculated by performing the Tauc’s plot. From the study, the grain size has been found to decrease with acid concentration while the band gap energy has been found to increase with increasing acid concentration. Further, the optical band gaps of the CNCs have been found to decrease with the increase in crystallite size. This shrinkage of the band gap has been attributed to the increased impurity concentration leading to the narrowing of the band gap due to the emerging of the impurity band formed by the overlapped impurity states

On the Spectroscopic Analyses of Polytetrafluoroethylene Coated with Nano ZnO and SiO2

On polytetrafluoroethylene (PTFE) polymer nanocomposites coated with basically two metal oxides (MOs), SiO2 and ZnO, as well as a mixture of the two MOs, density functional theory (DFT) computations were performed. The B3LYPL/LAN2DZ model was used to evaluate PTFE polymer nano composites suggested model structures. The physical and electrical properties of PTFE modified on surface with ZnO and SiO2 coated layer by layer change Total dipole moment (TDM) and HOMO/LUMO band gap energy ∆Eto be 13.0082 Debye and 0.6889 eV, respectively. Moreover, TDM and band gap energy (∆E) improved to 10.6053 Debye and 0.2727 eV, respectively, when the nanofiller was increased to 8 atoms. In addition, the results of the Molecular Electrostatic Potential (MESP) and the Quantitative Structure Activity Relationship (QSAR) showed that PTFE coated with ZnO and SiO2 improved electrical characteristics and thermal stability. As PTFE coated with ZnO and SiO2 layer by layer, all stability characteristics, including electrical and thermal stability, were enhanced. The improved PTFE can be used as a corrosion-inhibiting layer for astronaut suits, according to the predicted results.

One-Step Preparation of RGO/Fe3O4-Fevo4 Nanocomposites As Highly Effective Photocatalysts Under Natural Sunlight Illumination

The study used a one-step hydrothermal method to prepare Fe3O4-FeVO4 and xRGO/Fe3O4-FeVO4 nanocomposites. XRD, TEM, EDS, XPS, DRS, and PL techniques were used to examine the structurally and morphologically properties of the prepared samples. The XRD results appeared that the Fe3O4-FeVO4 has a triclinic crystal structure. Under hydrothermal treatment, (GO) was effectively reduced to (RGO) as illustrated by XRD and XPS results. UV-Vis analysis revealed that the addition of RGO enhanced the absorption in the visible region and narrowed the band gap energy. The photoactivities of the prepared samples were evaluated by degrading methylene blue (MB), phenol and brilliant green (BG) under sunlight illumination. As indicated by all the nanocomposites, photocatalytic activity was higher than the pure Fe3O4-FeVO4 photocatalyst, and the highest photodegradation efficiency of MB and phenol was shown by the 10%RGO/Fe3O4-FeVO4. In addition, the study examined the mineralization (TOC), photodegradation process, and photocatalytic reaction kinetics of MB and phenol.

Study of PVDF/ (Co-ZnFe2O4 and Cu-ZnFe2O4) nanocomposite for the piezo-phototronics applications

Polyvinylidene fluoride (PVDF) polymer is considered as a promising piezoelectric material whose optical properties need to be improved. Zinc ferrite is an excellent photoelectric material, in the present work it was doped separately by both cobalt and copper. Co-ZnFe2O4 and Cu-ZnFe2O4 nanoparticles were synthesized and characterized to be used as PVDF fillers, aiming to improve its optical properties. The optical properties as well as, the piezoelectric response of the prepared PVDF/ (Co-ZnFe2O4 and Cu-ZnFe2O4) nanocomposites were investigated. A remarkable improvement in the PVDF relative permittivity, optical conductivity, refractive index, non-linear susceptibility, and a great reduction in the band gap energy value is obtained by adding Co-ZnFe2O4 nanoparticles to it. However, Cu-ZnFe2O4 nanoparticles have limited improvement of the PVDF optical properties compared to the Co-ZnFe2O4 nanoparticles. The piezoelectric response of the PVDF polymer is clearly increased by the addition of both Co-ZnFe2O4 and Cu-ZnFe2O4 nanoparticles.

The Effect of Niobium and Rubidium Doping on the Energy Band Gap of a Lithium Tantalate (LiTaO3) Thin Film

Chemical solution deposition (CSD) is a technique for making a film by keeping synthetic arrangements on the outer layer of the substrate. The outcomes show that the band gap energy of the LiTaO3 film is 1 eV. Electrons are more effectively invigorated to the valence band than to the conduction band on the grounds that the energy required is not excessively huge. Niobium-doped LiTaO3 film has a band gap energy of 1.15 eV. A large amount of energy is needed for electrons to be energized from the valence band to the conduction band. The rubidium-doped LiTaO3 film has a band gap energy of 1.30 eV.

New Solid Solution and Phase Equilibria in the Subsolidus Area of the Three-Component CuO–V2O5–Ta2O5 Oxide System

The results of the study of the three-component system of CuO–V2O5–Ta2O5 oxides showed, inter alia, that in the air atmosphere in one of its cross-sections, i.e., in the CuV2O6–CuTa2O6 system, a new substitutional solid solution with the general formula CuTa2−xVxO6 and homogeneity range for x > 0.0 and x ≤ 0.3 is formed. The influence of the degree of incorporation of V5+ ions into the CuTa2O6 crystal lattice in place of Ta5+ ions on the unit cell volume, thermal stability and IR spectra of the obtained solid solution was determined. Moreover, the value of the band gap energy of the CuTa2−xVxO6 solid solution was estimated in the range of 0.0 < x ≤ 0.3, and on this basis, the new solid solution was classified as a semiconductor. On the basis of the research results, the studied system of CuO–V2O5–Ta2O5 oxides was also divided into 12 subsidiary subsystems.

Synthesis and Characterization of SnO2 Thin Film Semiconductor for Electronic Device Applications

Synthesis and characterization of SnO2 thin films with various types of doping materials such as aluminum, fluorine and indium have been successfully carried out. This study aims to determine the effect of various types of doping materials on the quality of thin films such as the energy band gap produced. The results showed that the higher the doping concentration, the more transparent the layer formed. In addition, the optical properties of thin films such as band gap energy are affected by the applied doping. The direct and indirect values ​​of the largest band gap energy for the percentage of 95:5% are 3.62 eV and 3.92 eV are found in the SnO2: In thin layer. Meanwhile, the lowest direct and indirect values ​​of band gap energy are in the thin layer of SnO2:(Al+F+In) for a percentage of 85:15%, namely 3.41 eV and 3.55 eV. The greater the amount of doping given, the smaller the bandgap energy produced. In addition, the more combinations of doping mixtures (aluminum, fluorine, and indium) given, the smaller the bandgap energy produced. This shows that the quality of a thin film of SnO2 produced is influenced by the amount of concentration and the type of doping used

Camptothecin-Carrying Cuco2s4 Nanoparticles: Sustained Drug Release And Anticancer Activity

Nanocarriers of anticancer drugs are delicately designed with precision addition at every attempt. In this paper, we report CuCo2S4 nanoparticles that show light-absorption in the NIR-II wavelength range and possess magnetic characteristics. The synthesized nanoparticles are characterized employing XRD, SEM, DLS, TGA, and XPS methods. The nanoparticles form a composite with biocompatible polymeric β-cyclodextrin. The nanoparticles possess a band gap energy of 2.25 eV. The magnetic property arises due to the cobalt-incorporation in the nanoparticles. The anticancer drug, camptothecin, is loaded in the nanocarrier with an 89% adsorption efficiency. The in vitro release of the drug occurs in a sustained fashion. Further, the in vitro anticancer potential of the nanocarrier is examined on breast cancer (MDA=MB-231) cell lines and the activities of the free- and the drug-loaded nanocarrier are compared. The cobalt-containing copper sulfide nanoparticle-poly-β-cyclodextrin composite works as a promising nanocarrier of camptothecin.

A Comparative Study of the Effect of Graphene Oxide, Graphitic Carbon Nitride, and Their Composite on the Photocatalytic Activity of Cu3SnS4

Photocatalysis has shown high potential in dealing with the ever-broadening problem of wastewater treatment, escalated by the increasing level of recalcitrant chemicals often referred to as emerging contaminants. In this study, the effect of support material on the photocatalytic activity of copper tin sulfide (Cu3SnS4) nanoparticles for the degradation of tetracycline as an emerging contaminant is presented. Graphene oxide, protonated graphitic carbon nitride, and a composite of graphitic carbon nitride and graphene oxide were explored as support materials for Cu3SnS4 nanoparticles. The nanoparticles were incorporated with the different carbonaceous substrates to afford graphene-supported Cu3SnS4 (GO-CTS), protonated graphitic carbon nitride-supported Cu3SnS4 (PCN-CTS), and graphene oxide/protonated graphitic carbon nitride-supported Cu3SnS4 (GO/PCN-CTS). Physicochemical, structural, and optical properties of the prepared nanocomposites were characterized using techniques such as Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis near infrared, and fluorescence spectrophotometry. The compositing of the Cu3SnS4 nanoparticles on the support materials was confirmed by the characterization techniques, and the optical properties of the composites were found to be influenced by the nature of the support material. The incorporation of CTS into the support materials resulted in a reduction in band gap energy with evaluated band gaps of 1.65, 1.46, 1.43 eV, and 1.16 eV. The reduction in band gap energy suggests the potential of the composites for enhanced photocatalytic activity. From the photocatalytic study, the degradation efficiency of tetracycline by CTS, PCN-CTS, GO-CTS, and PC/GO-CTS was 74.1, 85.2, 90.9, and 96.5%, respectively. All the composites showed enhanced activity compared to pristine CTS, and the existence of a synergy between GO and PCN when both were employed as support materials was observed. Based on the charge carrier recombination characteristics and the band edge potential calculations from the composites, a possible mechanism of action of each composite was proposed. This study therefore confirms the possibility of modulating the mechanism of action and subsequently the efficiency of semiconductor materials by altering the nature of the support material.