scholarly journals Synergistic Effects in a ZnO Powder-Based Coating Sequentially Irradiated with Protons, Electrons, and Solar Spectrum Quanta

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1021
Author(s):  
Mikhail M. Mikhailov ◽  
Semyon A. Yuryev ◽  
Alexey N. Lapin ◽  
Vadim V. Karanskiy
Keyword(s):  
Zinc Oxide ◽  
Absorption Coefficient ◽  
Near Infrared ◽  
Synergistic Effects ◽  
High Vacuum ◽  
Visible Region ◽  
Solar Spectrum ◽  
Complete Recovery ◽  
Solar Irradiation ◽  
Integral Absorption

The authors investigated the changes in diffuse reflectance spectra (ρλ) within 0.32–2.1 μm and integral absorption coefficient (as) of solar irradiation for a zinc oxide powder-based coating. The latter was consequently irradiated with protons (E = 3 keV, F ≤ 1 × 1016 cm−2), solar spectrum quanta (5 eq. of solar irradiation, 1 h), electrons (E = 30 keV, F = 1 × 1016 cm−2), and—repetitively—solar spectrum quanta (5 eq. of solar irradiation, 1 h). Following the irradiation procedure, the decrease in absorption coefficient varied from 0.044 to 0.036 and from 0.062 to 0.04, respectively. Additionally, it was shown that the solar spectrum quanta did not significantly affect the coating pre-irradiated with protons or electrons and did not change the value of induced absorption in the visible region (the latter being caused by the absorption of intrinsic point defects of the zinc oxide crystal lattice). The absorption coefficient degradation decreased under solar spectrum quanta irradiation, which was determined by the decrease in the concentration of free electrons that absorbed in the near-infrared (near-IR) region. ρλ spectra were measured in high vacuum in situ. A post-irradiation transfer of a coating into the atmosphere leads not only to the complete recovery of its reflectance, but also to partial translucence in comparison with the non-irradiated state.

Stability Studies on Optical and Structure Properties of Zinc Oxide Thin Films Exposed to Different Environment

2013 ◽  
Vol 667 ◽  
pp. 549-552
Author(s):  
A.S.M. Rodzi ◽  
Mohamad Hafiz Mamat ◽  
M.N. Berhan ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Zinc Oxide ◽  
Absorption Coefficient ◽  
Near Infrared ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Zno Films ◽  
Zno Thin Film ◽  
Oxide Thin Films

The properties of zinc oxide thin films were prepared by sol-gel spin-coating method have been presented. This study based on optical and electrical properties of ZnO thin film. The effects of annealing temperatures that exposed with two environments properties have been investigated. Environments exposed in room (27°C) and hot (80°C) temperatures which are stored by various days. Solution preparation, thin film deposition and characterization process were involved in this project. The ZnO films were characterized using UV-Vis-NIR spectrophotometer for optical properties. From that equipment, the percentage of transmittance (%) and absorption coefficient spectra were obtained. With two environments showed have different absorption coefficient are reveal and all films have low absorbance in visible and near infrared (IR) region but have high UV absorption properties. From SEM investigations the surface morphology of ZnO thin film shows the particles size become smaller and denser in hot temperatures while in room temperatures have porosity between particles.

scholarly journals Zinc Oxide Synthesis from Extreme Ratios of Zinc Acetate and Zinc Nitrate: Synergistic Morphology

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 570
Author(s):  
Sujittra Kaenphakdee ◽  
Pimpaka Putthithanas ◽  
Supan Yodyingyong ◽  
Jeerapond Leelawattanachai ◽  
Wannapong Triampo ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Zinc Acetate ◽  
Near Infrared ◽  
Synergistic Effects ◽  
Zinc Nitrate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Oxide Powders ◽  
Zno Powders

The synthesis of ZnO comprising different ratios of zinc acetate (ZA) and zinc nitrate (ZN) from the respective zinc precursor solutions was successfully completed via a simple precipitation method. Zinc oxide powders with different mole ratios of ZA/ZN were produced—80/1, 40/1, and 20/1. The crystallinity, microstructure, and optical properties of all produced ZnO powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis-NIR spectrophotometry. The average agglomerated particle sizes of ZnO-80/1, ZnO-40/1, and ZnO-20/1 were measured at 655, 640, and 620 nm, respectively, using dynamic light scattering (DLS). The optical properties of ZnO were significantly affected by the extreme ratio differences in the zinc precursors. ZnO-80/1 was found to have a unique coral-sheet structure morphology, which resulted in its superior ability to reflect near-infrared (NIR) radiation compared to ZnO-40/1 and ZnO-20/1. The NIR-shielding performances of ZnO were assessed using a thermal insulation test, where coating with ZnO-80/1 could lower the inner temperature by 5.2 °C compared with the neat glass substrate. Due to the synergistic effects on morphology, ZnO-80/1 exhibited the property of enhanced NIR shielding in curtailing the internal building temperature, which allows for its utilization as an NIR-reflective pigment coating in the construction of building envelopes.

Synthesis Study of Silver-Doped Zinc Oxide for Near-Infrared Shielding Applications

2020 ◽  
Vol 1007 ◽  
pp. 143-147
Author(s):  
Sujittra Kaenphakdee ◽  
Supan Yodyingyong ◽  
Jeerapond Leelawattanachai ◽  
Wannapong Triampo ◽  
Noppakun Sanpo ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Property ◽  
Silver Nitrate ◽  
Zno Nanoparticles ◽  
Zinc Acetate ◽  
Near Infrared ◽  
Visible Region ◽  
Zinc Nitrate ◽  
Precipitation Method ◽  
Doped Zno

Undoped ZnO and Ag-doped ZnO were prepared to use as near-infrared (NIR) shielding by simple precipitation method with zinc acetate and zinc nitrate as Zn precursor and silver nitrate as Ag precursor. The Ag-doped ZnO and undoped ZnO were characterized by XRD, SEM, and UV-vis-NIR spectrophotometer. The NIR reflectance performance reveals that Ag-doping improves the NIR shielding and optical property of pure ZnO. The 10 mol% Ag loading shows the lowest reflection in the visible region of about 15% and the highest reflection in the NIR region of about 50%. It not only shows the best NIR reflection but also exhibits the best thermal insulation. It reduces the inner temperature of the in-lab setup to mimic a house by 7.5°C when compared to the uncoated glass window. It is concluded that 10 mol% Ag-doped ZnO nanoparticles can result in UV-NIR shielding coatings.

scholarly journals Enhanced solar energy absorption on nitrogen-doped carbon nanotubes decorated with gold-palladium bimetallic nanoparticles

2018 ◽  
Vol 22 (Suppl. 2) ◽  
pp. 701-708 ◽  
Author(s):  
Lingling Wang ◽  
Guihua Zhu ◽  
Long Shen ◽  
Wei Yu ◽  
Dahai Zhu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Near Infrared ◽  
Bimetallic Nanoparticles ◽  
Visible Region ◽  
Infrared Region ◽  
Thermal Conversion ◽  
Solar Irradiation ◽  
Alloy Nanoparticles ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon

Gold-palladium alloy nanoparticles decorated on nitrogen-doped carbon nanotubes (Au-Pd/N-CNT) were prepared by using polyethylene imine reduction method. Polyethylene acts as not only a stabilizing agent, but also a reducing agent, leading to nucleation and growth of nanoparticles on the N-CNT surfaces. All the N-CNT-based nanofluids show broadband absorption across the visible region and near infrared region. The Au-Pd/N-CNT nanofluids absorb more solar irradiation compared with monometallic Pd/N-CNT or Au/N-CNT nanofluid. The photo-thermal conversion efficiency of Au-Pd /N-CNT nanofluids is 62.3%, compared with 53.3% and 57% for Pd/N-CNT and Au/N-CNT, respectively. This enhancement was mainly due to the synergetic effects of N-CNT and Au-Pd alloy nanoparticles.

Extension of the photoresponse of semiconducting zinc oxide electrodes by 3d-impurities absorbing in the visible region of the solar spectrum

1985 ◽  
Vol 188 (1-2) ◽  
pp. 167-187 ◽  
Author(s):  
Denis Fichou ◽  
Joseph Pouliquen ◽  
Jean Kossanyi ◽  
Mohamed Jakani ◽  
Guy Campet ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Visible Region ◽  
Solar Spectrum ◽  
Oxide Electrodes ◽  
3D Impurities

Enhanced visible-light absorption of mesoporous TiO2 by co-doping with transition-metal/nitrogen ions

2013 ◽  
Vol 1547 ◽  
pp. 115-119 ◽  
Author(s):  
J. E. Mathis ◽  
Z. Bi ◽  
C. A. Bridges ◽  
M. K. Kidder ◽  
M. P. Paranthaman
Keyword(s):  
Transition Metals ◽  
Band Gap ◽  
Near Infrared ◽  
Solar Spectrum ◽  
Visible Spectrum ◽  
Solar Irradiation ◽  
Major Drawback ◽  
Co Doping ◽  
Energy Applications ◽  
Sufficient Energy

ABSTRACTTitanium (IV) oxide, TiO2, has been the object of intense scrutiny for energy applications. TiO2 is inexpensive, non-toxic, and has excellent corrosion resistance when exposed to electrolytes. A major drawback preventing the widespread use TiO2 for photolysis is its relatively large band gap of ∼3eV. Only light with wavelengths shorter than 400 nm, which is in the ultraviolet portion of the spectrum, has sufficient energy to be absorbed. Less than 14 percent of the solar irradiation reaching the earth’s surface has energy exceeding this band gap. Adding dopants such as transition metals has long been used to reduce the gap and increase photocatalytic activity by accessing the visible part of the solar spectrum. The degree to which the band gap is reduced using transition metals depends in part on the overlap of the d-orbitals of the transition metals with the oxygen p-orbitals. Therefore, doping with anions such as nitrogen to modify the cation-anion orbital overlap is another approach to reduce the gap. Recent studies suggest that using a combination of transition metals and nitrogen as dopants is more effective at introducing intermediate states within the band gap, effectively narrowing it. Here we report the synthesis of mesoporous TiO2 spheres, co-doped with transition metals and nitrogen that exhibit a nearly flat absorbance response across the visible spectrum extending into the near infrared.

scholarly journals Plasmon-Enhanced Sunlight Harvesting in Thin-Film Solar Cell by Randomly Distributed Nanoparticle Array

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1380
Author(s):  
Marwa M. Tharwat ◽  
Ashwag Almalki ◽  
Amr M. Mahros
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Near Infrared ◽  
Structural Parameters ◽  
Visible Region ◽  
Nanoparticle Array ◽  
Solar Energy Harvesting ◽  
Infra Red ◽  
Crucial Parameter

In this paper, a randomly distributed plasmonic aluminum nanoparticle array is introduced on the top surface of conventional GaAs thin-film solar cells to improve sunlight harvesting. The performance of such photovoltaic structures is determined through monitoring the modification of its absorbance due to changing its structural parameters. A single Al nanoparticle array is integrated over the antireflective layer to boost the absorption spectra in both visible and near-infra-red regimes. Furthermore, the planar density of the plasmonic layer is presented as a crucial parameter in studying and investigating the performance of the solar cells. Then, we have introduced a double Al nanoparticle array as an imperfection from the regular uniform single array as it has different size particles and various spatial distributions. The comparison of performances was established using the enhancement percentage in the absorption. The findings illustrate that the structural parameters of the reported solar cell, especially the planar density of the plasmonic layer, have significant impacts on tuning solar energy harvesting. Additionally, increasing the plasmonic planar density enhances the absorption in the visible region. On the other hand, the absorption in the near-infrared regime becomes worse, and vice versa.

scholarly journals Biomimetic Synthesis, Characterization, and Evaluation of Fluorescence Resonance Energy Transfer, Photoluminescence, and Photocatalytic Activity of Zinc Oxide Nanoparticles

2021 ◽  
Vol 13 (4) ◽  
pp. 2004
Author(s):  
Udari Wijesinghe ◽  
Gobika Thiripuranathar ◽  
Haroon Iqbal ◽  
Farid Menaa
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Solar Irradiation ◽  
Zno Nps ◽  
Fluorescence Resonance

Owing to the development of nanotechnology, biosynthesis of nanoparticles (NPs) is gaining considerable attention as a cost-effective and eco-friendly approach that minimizes the effects of toxic chemicals used in NP fabrication. The present work reports low-cost phytofabrication of zinc oxide (ZnO) NPs employing aqueous extracts of various parts (leaves, stems, and inflorescences) of Tephrosia purpurea (T. purpurea). The formation, structure, morphology, and other physicochemical properties of ZnO NPs were characterized by ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). UV–Vis spectral analysis revealed sharp surface plasmon resonance (SPR) at around 250–280 nm, while the XRD patterns confirmed distinctive peaks indices to the crystalline planes of hexagonal wurtzite ZnO NPs. TEM analysis confirmed the presence of spherical-shaped ZnO NPs with average particle sizes (PS) between 25–35 nm, which was in agreement with the XRD results. FTIR analysis revealed that phenolics, flavonoids, amides, alkaloids, and amines present in the plant extract are responsible for the stabilization of the ZnO NPs. Further, the hydrodynamic diameter in the range of 85–150 nm was measured using the DLS technique. The fluorescence resonance energy transfer (FRET) ability of biogenic ZnO NPs was evaluated, and the highest efficiency was found in ZnO NPs synthesized via T. purpurea inflorescences extract. Photoluminescence (PL) spectra of biogenic ZnO NPs showed three emission peaks consisting of a UV–Vis region with high-intensity compared to that of chemically synthesized ZnO NPs. The biosynthesized ZnO NPs showed photocatalytic activity under solar irradiation by enhancing the degradation rate of methylene blue (MB). Among the prepared biogenic ZnO NPs, T. purpurea leaves mediated with NPs acted as the most effective photocatalyst, with a maximum degradation efficiency of 98.86% and a half-life of 84.7 min. This is the first report related to the synthesis of multifunctional ZnO NPs using T. purpurea, with interesting characteristics for various potential applications in the future.

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