In this contribution an exceptionally simple, cost effective and reliable method for biosynthesis of ZnO nanoparticles through using Sageretia thea natural extracts as an effective chelating agent. The morphological analysis shows ZnO has nanoscale particles size 28.09 nm ± 5 nm, crystalline and possess distinct nanostructure hexagonal wurtzite structure. Effects of heat on ZnO synthesised at room temperature caused bonds with in the molecule to be broken exhibited continuous weight loss with 3 quasi sharp changes and 3 endothermic peaks occurring at 79°C, 228°C and 300°C. A proposed mechanism of reaction for Zn(NO3)2 6H2O precursor with bioactive compounds in Sageretia thea extract such as phenolic acid, flavonoids, natural sterolin and vitamin based compounds to form ZnO nanoparticles. Electrochemically ZnO nanoparticles are electroactive by exhibiting charge transfer resistance (Rct) 82006 Ω and bare GCE 3.7707 × 105 Ω. Showed good catalytic and conductivity which can be applied for pseudo capacitors.

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The Study of Structural, Physical and Electrochemical Activity of Zno Nanoparticles Synthesized by Green Natural Extracts of Sageretia Thea

ZnO-based ultraviolet (UV) photodetector can be easily fabricated by using sol-gel spin-coating method, however, the crystallization of amorphous state ZnO thin films is necessary to fabricate high performance UV photodetector. Thus, we devised a thermal dissipation annealing (TDA) method in which the heat transfer to the ZnO thin films can be synchronized with the heat release from the substrate. It was found that sol-gel spin-coated ZnO thin films can be crystallized through the mobility difference of ZnO molecules placed at the surface of ZnO thin films. Also, UV photodetector based on ZnO thin films annealed with the TDA method exhibited faster rise and decay time constant (τr = 35 ms and τd = 73 ms, respectively), a higher on/off current ratio, and reproducible photocurrent characteristics compared to that of the ZnO thin films annealed by using furnace and IR lamp. Therefore, these results indicated that the TDA method is a feasible alternative route for the fabrication of ZnO based high performance optoelectronic devices.

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Crystallization of ZnO thin films via thermal dissipation annealing method for high-performance UV photodetector with ultrahigh response speed.

Characterization of Ag-doped ZnO thin films by spray pyrolysis and its using in enhanced photoelectrochemical performances

Study on Co-doped ZnO comparatively by first-principles calculations and relevant experiments

This paper highlights some physical investigations on GO-doped ZnO thin films synthesized using zinc acetate dehydrate isopropyl alcohol and graphene oxide (GO) as doping element in a starting solution using a mini-spray pyrolysis process. These films, with thicknesses less than 400 nm, crystallize in hexagonal wurtzite structure with a preferential orientation according to (002) direction. The morphological characterization revealed a good homogeneity at the surface with good dispersion of graphene nanoparticles over the entire surface, especially for 2% GO doping. The refractive index and thickness of ZnO:GO thin films have been calculated using the envelope method. A decrease in the refractive index with doping was observed which indicates an increase of free carriers. In addition, band gap and Urbach energies were also deducted from the absorption coefficient. Indeed, this layer provides an increase in the dielectric constant e2 in the IR range, which is a proof of creating free electrons. Finally, the 2% GO doping gives the best optoelectrical properties of ZnO thin films which can be used in a forthcoming application for future optoelectronics.

Physical properties of graphene oxide GO-doped ZnO thin films for optoelectronic application

Extraordinary near-band-edge photoluminescence in the highly epitaxial ZnO films deposited by PLD

Enhanced resonant Raman scattering and optical emission of ZnO/ZnMgO multiple quantum wells

Enhanced photoluminescence of Co2+ ions in ZnCoO/ZnMgO multiple quantum wells and the fluorescence energy transfer mechanism

Diagnostic study of interface materials of co-deposition simulating impurity relevant to international thermonuclear experimental reactor by using calibration-free laser-induced breakdown spectroscopy

J.M. Ashfaq

Papers

Extraordinary near-band-edge photoluminescence in the highly epitaxial ZnO films deposited by PLD

Enhanced resonant Raman scattering and optical emission of ZnO/ZnMgO multiple quantum wells

Enhanced photoluminescence of Co2+ ions in ZnCoO/ZnMgO multiple quantum wells and the fluorescence energy transfer mechanism

Diagnostic study of interface materials of co-deposition simulating impurity relevant to international thermonuclear experimental reactor by using calibration-free laser-induced breakdown spectroscopy