Synthesis and Optical Properties of Eu3+ Doped NaYF4 and KYF4 Micro/Nanocrystals

2016 ◽  
Vol 16 (4) ◽  
pp. 3857-3860 ◽  
Author(s):  
Siling Guo ◽  
Chunyan Cao ◽  
Renping Cao

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.

2013 ◽  
Vol 634-638 ◽  
pp. 2261-2263
Author(s):  
Khun Ngern Supunnee ◽  
Vatcharinkorn Mekla ◽  
Eakkarach Raksasri

In this work optical properties of CuO nanostructure were studied. CuO nanostructure were synthesized by the hydrothermal treatment method. The structural and chemical natures of the obtained materials were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and study optical properties by UV-visible spectral. The XRD patterns of the CuO nanostructures indicated that CuO phases (JCPDS 05- 0661). The top-view SEM images, it can be seen clearly that high-density, horizontally scattered nanorod were grown on the product prepared at concentration of NaOH (aq) 7.5 M at 180 C for 12 h. The spectral of UV-vis data recorded showed the strong cut off at 341 nm.


2013 ◽  
Vol 634-638 ◽  
pp. 2258-2260
Author(s):  
Sopa Noontasa ◽  
Vatcharinkorn Mekla ◽  
Sert Kiennork

In this work optical properties of CuO nanostructure were studied. CuO nanostructure were synthesized by the hydrothermal treatment method. The structural and chemical natures of the obtained materials were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and study optical properties by UV-visible spectral. The XRD patterns of the CuO nanostructures indicated that CuO phases (JCPDS 05- 0661). The top-view SEM images, it can be seen clearly that high-density, horizontally scattered nanorod were grown on the product prepared at concentration of NaOH (aq) 7.5 M at 180 C for 12 h. The spectral of UV-vis data recorded showed the strong cut off at 341 nm.


1994 ◽  
Vol 49 (10) ◽  
pp. 977-982 ◽  
Author(s):  
Maria Paola Medda ◽  
Giorgio Piccaluga ◽  
Gabriella Pinna ◽  
Marco Bettinelli ◽  
Guy Cormier

AbstractTwo vitreous samples, 0.9 Z n (PO3)2 • 0.1 Eu(PO3)3 and pure zinc metaphosphate, were examined by X-ray diffraction to determine the local environment of the Eu3+ ion. Using a difference procedure involving the radial functions of the two glasses, the results indicate that the rare-earth ion is surrounded on average by a polyhedron of about 7.4 oxygens at 2.36 A and about 1.6 oxygens at 2.68 Å. A possible different coordination of the zinc ion in the two samples, suggested by the experimental findings, is discussed.


2021 ◽  
Vol 12 (4) ◽  
pp. 2523-2529
Author(s):  
Daniel Sam N ◽  
Anish C I ◽  
Sabeena G ◽  
Rajaduraipandian S ◽  
Manobala ◽  
...  

Sol gel methods were used for the study of the antimicrobial activity of Cd-TiO2 against gram-negative and positive bacteria. These Cd-TiO2 have been characterized by various optical and techniques. They have been exhibited by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, and infrared spectroscopy. The structures of the various XRD patterns indicate that the product has a structure. The particle size of Cd-TiO2 is 35nm. The SEM images confirm the spherical appearance of the sample. The energy X-ray spectra have been confirmed as well and then C, O, Ti, Cd, Pt element are present in Cd-TiO2. The weight percentage of Cadmium is 5.8%, Ti is 51.03%, C is 5.13% and O is 31.75% in Cd-TiO2. BET image shows that the major pore size distribution of Cd-TiO2 is ranged from 2.24 nm. The Cd-TiO2 that the antibacterial activity when tested against the pathogens only gram-negative bacteria such as Pseudomonas. The zone of minimum inhibition concentration was measured in a range of 20mm in 25μl and 30mm in 100μl.


1998 ◽  
Vol 4 (S2) ◽  
pp. 342-343 ◽  
Author(s):  
S. D. Walck ◽  
P. Ruzakowski-Athey

The analysis of Selected Area Diffraction (SAD) patterns that are collected from a single phase material having sufficient crystallites to provide continuous rings is relatively straightforward. However, when this condition is not met and there may be several phases present having rings of a spotty nature, the pattern is complex and can be quite difficult to analyze manually because of the vast number of discrete spots. WinJade from MDI is an X-ray diffraction (XRD) analysis program with an Electron Diffraction Program Module (EDPM) that can be used to aid in the analysis of SAD patterns. The EDPM produces Integrated Circular Density Plots (ICDP), which are one-dimensional intensity profiles plotted as a function of equivalent XRD 20 values or crystal d-spacings. These ICDP's can be overlayed with XRD patterns or with reference lines from the NIST and JCPDS crystalline databases for direct comparisons.


2017 ◽  
Vol 751 ◽  
pp. 825-830 ◽  
Author(s):  
Phuri Kalnaowakul ◽  
Tonghathai Phairatana ◽  
Aphichart Rodchanarowan

In this study, the photocatalytic properties and morphology of TiO2, ZnO, Ag-graphene-zinc oxide (Ag-G-ZnO) and Ag-graphene-titanium dioxide (Ag-G-TiO2) nanocomposite were compared. The Ag-G-ZnO and Ag-G-TiO2 nanocomposite were successfully prepared by thermal decomposition of colloidal solution. These prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy and photocatalytic activities. The results from XRD patterns show that Ag-G-TiO2 composites and the Ag-G-ZnO nanocomposites were in the form of fcc and hcp crystal structure, respectively. The SEM images show that at calcination of 500 °C for 3 h, the composite thin film of Ag-G-ZnO and Ag-G-TiO2 were homogenous. In the case of the photocatalytic experiments using methylene blue dye (MB) under UV irradiation, the order of the photocatalytic activities from high to low performances are Ag-G-ZnO, Ag-G-TiO2, ZnO and TiO2, respectively.


2018 ◽  
Vol 10 (3) ◽  
pp. 409-412
Author(s):  
Shihua Zhao

ZnO/AAM (anodic alumina membrane) arrays were prepared by an electrodeposition method and X-ray diffraction (XRD) patterns show that the characteristic diffraction peaks of ZnO appear, such as the lattice planes of (100), (002), and (102), moreover, the diffraction peaks of Al2O3 are dominated. Scanning electron microscopy (SEM) images show that the average sizes of the ZnO particles are about 100 nm corresponding to the channel diameters of AAM, and the ZnO arrays are composed of those close particles linked together. The photoluminescence emission spectra express that the as-prepared ZnO arrays can give out relatively pure ultraviolet light (395 nm) from the excitons.


2013 ◽  
Vol 652-654 ◽  
pp. 563-566
Author(s):  
Xia Wang ◽  
Chang Cheng Liu ◽  
Zhen Hua Liang ◽  
Gui Hua Peng ◽  
Xiao Bao Han

Hollow spherical CaMoO4:Eu3+, Li+red phosphors have been successfully synthesized by spray pyrolysis method. The crystalline phase, morphology and luminescent properties of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence emission spectra (PL). The XRD results demonstrated that all the diffraction peaks of the samples can be well indexed to the tetragonal phase of CaMoO4. The SEM images showed that the particles were composed of hollow spheres, whose diameters are about 1.4 μm. The as-prepared CaMoO4:Eu3+, Li+hollow spheres show a strong red emission corresponding to the5D0-7F2transition of the Eu3+ ions under ultraviolet light.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3333
Author(s):  
Andrei S. Tutantsev ◽  
Ekaterina I. Marchenko ◽  
Natalia N. Udalova ◽  
Sergey A. Fateev ◽  
Eugene A. Goodilin ◽  
...  

Layered hybrid halide perovskites (LHHPs) are an emerging type of semiconductor with a set of unique optoelectronic properties. However, the solution processing of high-quality LHHPs films with desired optical properties and phase composition is a challenging task, possibly due to the structural disorder in the LHHP phase. Nevertheless, there is still a lack of experimental evidence and understanding of the nature of the structural disorder in LHHPs and its influence on the optical properties of the material. In the current work, using 2D perovskites (C4H9NH3)2(CH3NH3)n−1PbnI3n+1 (further BA2MAn−1PbnI3n+1) with n = 1–4 as a model system, we demonstrate that deviations in LHHPs optical properties and X-ray diffraction occur due to the presence of continuous defects—Stacking Faults (SFs). Upon analyzing the experimental data and modeled XRD patterns of a possible set of stacking faults (SFs) in the BA2MAPb2I7 phase, we uncover the most plausible type of SFs, featured by the thickness variation within one perovskite slab. We also demonstrate the successful suppression of SFs formation by simple addition of BAI excess into BA2MAn−1PbnI3n+1 solutions.


Author(s):  
M. A. Ramazanov ◽  
S. G. Nuriyeva ◽  
H. A. Shirinova ◽  
A. H. Karimova ◽  
M. A. Nuriyev

Ag2S/ZnS nanocomposites were synthesized using a novel method, and their structural features and optical properties were also investigated. For the structural investigation of the core/shell-like nanocomposites, X-ray powder diffraction technique (XRD) and scanning electron microscopy (SEM) were used. Optical features of Ag2S/ZnS nanocomposites were studied by UV-Vis absorption and photoluminescence spectroscopy (PL). According to the SEM images, the sizes of the Ag2S, ZnS nanoparticles and Ag2S/ZnS core/shell-like nanocomposites are in the region of the 10–15; 25–50 and 15–80 nm, respectively. Furthermore, the absorption spectroscopy indicates that the bandgap of Ag2S/ZnS nanocomposites is approximately 2.4 eV. By comparison of the intensities of the emission spectra, it was clear that the intensity of Ag2S/ZnS is much lower than that of ZnS.


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