We reported an easy fabrication method to realize ZnO-based microcavities with various cavity shapes by focused ion beam (FIB) milling. The optical characteristics of different shaped microcavities have been systematically carried out and analyzed. Through comprehensive studies of cathodoluminescence and photoluminescence spectra, the whispering gallery mode …
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Chromium (Cr)-doped zinc oxide (ZnO) nanorods with wurtzite hexagonal structure were prepared through a thermal decomposition technique. The concentration effect of the Cr doping on the structural, morphological, and optical properties of the ZnO nanorods was established by correlating various measurements: transmission electron microscopy (TEM), …
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The average grain size of the ZnO nanoparticles is in the range of 24–40 nm, depending on the mechanical grinding time. The UV–vis diffuse reflectance spectrum of the ZnO nanoparticles indicates a band gap of about 3.3 eV with an onset of absorption at about 3.1 eV, showing a weak red shift compared to 3.37 eV for the bulk ZnO.
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band gap energy of ZnO and Ag-ZnO nanorods the diffuse reflectance spectroscopy (DRS) analysis was applied (Avaspec-2048 TEC spectrometer). To detect the trace of Ag in the solution, atomic absorption spectrometry (AAS) (VARIAN, model AA240) was employed. For analysing the composition of photocatalyst, changes in the concentration of AY23 were
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UV–vis diffuse reflection spectra: (a) ball milling time 3 h, (b) ball milling time 6 h, and (c) ball milling time 12 h. In the process of ball milling, the crystal lattices of the CaFe 2 O 4 and ZnO undergo severe plastic deformation, producing stresses and strains.
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This work proposes a new approach on exploring Zinc Oxide (ZnO) nanodiffusers to improve organic solar cell (OSC) performance. ZnO nanoparticles (NPs) dispersed on the OSC top surface can reduce the device reflection and enhance the absorption of solar radiation in the photovoltaic active layer, due to the introduction of non-orthogonal light pathways in the …
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Phase development during high-energy ball-milling of zinc oxide and iron – the impact of grain size on the source and the degree of contamination. ...
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ZnO nanostructures show diffuse reflectance from 57 % to 14 % in the NIR range (700 – 2500 nm). KEYWORDS Near infrared reflection, cool paint, metal oxide, TiO 2, ZnO . GNS Science Report 2013/39 1 1.0 INTRODUCTION Light energy from the sun spans a wide range of wavelengths. Only small portion of the total
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The UV–vis diffuse reflectance spectra for different amounts of ZnO quantum dots loaded onto KNb 3 O 8 nanosheets are illustrated in Figure 7. The steep absorption edge of the pure KNb 3 O 8 nanosheets occurred around 343 nm under UV light owing to its large intrinsic band gap. When increasing the ZnO quantum dot loading, the sample displayed ...
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In this paper, p-type ZnO powder was prepared by decomposition of zinc nitrate at 350 °C for 1 h. p-n junction photocatalyst p-ZnO/TiO 2 was prepared by ball milling of TiO 2 in H 2 O solution doped with p-ZnO. The p-n junction photocatalyst p-ZnO/TiO 2 was characterized by UV-vis diffuse reflection spectrum, scanning electron microscopy (SEM), X-ray powder diffraction …
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Abstract. Solid-state process of introducing oxygen vacancies into the structure of TiO 2 and ZnO particles was studied. The phase transformations of metal oxides throughout the process were examined by X-ray diffraction (XRD). The influence of the loaded mechanical stress on the band gap was studied by diffuse reflectance spectroscopy (DRS).
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Diffuse reflectance spectra 2 UV-vis diffuse reflectance spectra are shown in Fig. 2. A pure ZnO sample could absorb only ultra-violet light. A spectrum of N-doped Fe 2 O 3-ZnO sample demonstrated a reflectance, covering wave-lengths from 200 to 800 nm. A decrease of the reflectance was observed for doped mixed oxide
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Lao et al. [23] used nano-milling of ZnO powder with either YSZ or Al 2 O 3 balls and studied the possible contamination of the milled product and the effect of the milling media on the ... The diffuse reflectance spectra showed characteristic 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g transitions, while the photoluminescence emission spectrum ...
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ZnO:Fe2O3 = 1:1 before milling. All the diffraction peaks of mechanical activated zinc oxide and 0.3 FZ sample can be well indexed to the hexagonal phase ZnO (JCPDS card no. 36-1451. A decrease in the reflection intensity was observed during milling. As milling proceeds broadening of diffraction peaks is observed due to grain size reduction ...
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To understand wave diffuse reflection, consider a one-dimensional nanoscaled rough surface between ZnO and air in the context of the extinction theorem 12,13,14,15.Two length scales are used to ...
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Our recent study in this journal highlighted misassignments of surface intermediates of diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements of published Cu/ZnO (CZ) catalyst systems for methanol synthesis.
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Synthesis of Wurtzite Nano-crystalline ZnO-CoO Pigment by High Energy Milling ... diffuse reflectance and Scanning Electron Microscopy. The results ...
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10%Diffuse Reflectance Measurements of the Synthesized Cr-Doped ZnO Nanopigments Diffuse reflectance (DR) measurement give a clear identification about the ability of usage of the powdered materials as cool nanopigments. In this respect, Fig. 6 shows DF UV–Vis–NIR spectra for the investigated nanopigments.
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Further, the diffuse reflectance UV–Vis studies demonstrated a blue-shift in the reflectance spectrum for the bipolar-made oxide. This was also an indication of defects in the ZnO lattice, which related to the formation of shallow levels in the bandgap of the material.
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ZnO nanocomposites by planetary ball milling and we have also investigated the structural, optical and antibacterial properties of CeO 2 / ZnO nanocomposites. 2. ... The diffuse reflectance spectra were recorded on a 2450 Shimadzu UV-vis spectrophotometer. The room temperature photoluminescence (PL) spectra
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The low diffuse reflection is likely to be caused by non-uniform deposited thin films. This means that parts of the diffuse transmitted light that reaches the glass back end will be reflected back into the glass instead of being transmitted through it, similar to a conventional light trapping and back-reflecting cover glass structure ( Deubener ...
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The average diameter of the ZnO NPs was found to be the smallest among the above methods when the capping agent ethylene glycol was used (Method 3.6). 4.3 Diffuse reflectance spectroscopy (DRS) The diffuse reflectance spectra of all of the ZnO samples are shown in Fig. 5. Strong reflections were found above 400 nm for all samples.
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The C 3 N 4 /ZnO composite photocatalysts were synthesized by mechanical milling combined with a calcination process. Various ratios of melamine and ZnO powders were milled by a planetary ball mill for 10 h. After heating at 540 ∘ C for 3 h in air, melamine was converted to C 3 N 4 but the formation of C 3 N 4 depended on the ratios of the melamine and …
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Novel green photocatalysts based on ZnO in the presence of arabic gum (AGZ) or karaya gum (KGZ) were synthesized by a sol–gel method for photocatalytic performance. The materials were characterized by XRD, FTIR spectroscopy, SEM, nitrogen adsorption/desorption, and PL and diffuse reflectance spectroscopy. Ph New Talent: Americas
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The effect of ball milling and Ag doping content on the absorption spectra and the band gap energy of TiO 2 were also analyzed with diffuse reflectance spectroscopy. It has been observed that by the introduction of Ag, the absorption edge of samples shifted towards the visible light region. 3.6
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Diffuse reflectance spectra of ZnO, Ga 2 O 3, Ca 3 (PO 4) 2 coating before (a) and after proton irradiation (b). After proton irradiation, significant decline in reflectance of ZnO coating can be observed, as is evidenced from the yellowing appearance of the irradiated surface that shown in …
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This study is aimed at developing a simple and low-cost method to fabricate ZnO-loaded porous activated carbon (AC-ZnO) prepared from the Algerian olive-waste cakes and utilize it as a photocatalyst for the degradation of Ethyl Violet dye. The synthesized AC-ZnO material was characterized using powder X-ray diffraction, BET surface area measurements, Raman …
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The optical absorption of the ZnO arrays@BiOI nanosheets composite was investigated by UV-Vis diffuse reflectance spectra. The photocatalytic degradation of methanol orange under visible light shows that the obtained ZnO arrays@BiOI nanosheets heterostructures exhibit enhanced photocatalytic activity, contrasting to the sum of BiOI nanosheets ...
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Figure 3 shows UV-Vis-NIR diffuse reflectance spectra of the Zn (1-x) Ni x Fe 2 O 4 pigments. All pigments show low reflectance in a wavelength range of around 300 to 650 nm, and characteristic absorption bands of ZnFe 2 O 4 at around 700-800 and 1000-1400 nm, which are attributed to 6A 1g→ 4T 2g and 6A 1g→ 4T 1g for d-d elec-2 2.
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source (ZnO-am). The mechanical activated ZnO sample was also prepared for comparison (ZnO-MA). As-milled samples were calcined at 673 K. The so prepared samples have been characterized by X-ray diffraction (XRD), diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy . The XRD analysis shows wurtzite crystal structure of
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Diffuse reflection is a well-known but important optical phenomenon that is commonly observed in daily life 1. Light reflects and diffuses in many different directions from surfaces that are...
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This study aimed to modify an EQUIA coat (EC; GC, Japan) by incorporating 1 and 2 wt.% of zinc oxide (ZnO; EC-Z1 and EC-Z2) and titanium dioxide (TiO2; EC-T1 and EC-T2) nanoparticles, whereby structural and phase analyses were assessed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. Thermogravimetric …
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Structural and microstructural changes during the ball-milling (up to 30 h) were monitored using X-ray powder diffraction, field emission scanning electron microscopy (FE-SEM) and UV-Vis diffuse reflectance spectroscopy. The mechanism of iron oxidation was determined from the results of Mössbauer spectroscopy.
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According to UV-visible diffuse reflectance spectroscopy, the evident energy band gap value of the SnO(2)-ZnO photocatalyst was estimated to be 3.23 eV to be compared with those of pure SnO(2), that is, 3.7 eV, and ZnO, that is, 3.2 eV, analogues.
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or diffuse reflectance spectroscopy. For a rough powder such as ZnO, diffuse reflectance is the method of choice. This application note details the use of the Harrick Praying Mantis™ diffuse reflection accessory in observing the shift in the visible absorption band of ZnO upon heating within the Harrick High Temperature Reaction Chamber.
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Mechanical milling of commercial ZnO and SnO 2 was used to produce a ZnO/SnO 2 composite with a high density of surface defects; in particular, zinc interstitials (Zn i) and oxygen vacancies (V O).To determine the impact of surface defects on photocatalytic activity, the relative concentration ratio of bulk defects to surface defects was modified by annealing at 400 and …
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