A comprehensive study on the impact of Gd substitution on structural, optical and magnetic properties of ZnO nanocrystals

Punia, Khushboo; Lal, Ganesh; Dalela, S.; Dolia, S. N.; Alvi, P. A.; Barbar, S. K.; Modi, K. B.; Kumar, Sudhish

doi:10.1016/j.jallcom.2021.159142

Cited by 67 publications

(16 citation statements)

References 96 publications

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“…1 duced in the Ni 0.95 Cr 0.05 nanostructures embedded in the Ag matrix is about 0.036, estimated from the XRD data (Kaushik et al 2013;Punia et al 2021aPunia et al , 2021b, is slightly higher than Ni 0.95 Cr 0.05 NCs (0.026) and Ni 0.95 Cr 0.05 nanogranular thin ilms (0.022). 3 Ni 0.95 Cr 0.05 nanogranular thin ilms: These were deposited by conventional sputtering of Ni 0 .…”

Section: Methodsmentioning

confidence: 88%

Design of various Ni–Cr nanostructures and deducing their magnetic anisotropy

et al. 2021

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Understanding the efects of interparticle interactions is a vital problem because magnetic nanoparticles showcase a variety of magnetic conigurations due to diferent contributions to their total energy. To derive reliable and robust properties from magnetic nanoparticles, it is, thus, necessary to understand the competition between particle anisotropy and interparticle interactions that deine the magnetic state of nanoparticles, where size control plays an important role. Here, we apply the random anisotropy model (RAM) that considers various magnetic interactions to selectively prepared NiCr nanostructures (NiCr dense nanoclusters, nanogranular NiCr thin ilms, and Ag(NiCr) nanocomposites) with diferent interparticle interactions. The estimated single-particle magnetic anisotropy K values (2.82 − 12.3 × 10 4 J/m 3 ) and careful analysis of magnetization behavior for these nanostructures reveal that orbital hybridization, surface segregation, and interface character govern the magnetic interactions among nanoparticles. Our study demonstrates how magnetic behaviors vary in these diferent magnetic systems consisting of superparamagnetic (SPM) and ferromagnetic (FM) contributions speciic to magnetic interactions.

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Section: Methodsmentioning

confidence: 88%

Design of various Ni–Cr nanostructures and deducing their magnetic anisotropy

et al. 2021

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“…To attest the defects emerging from the dopant’s inclusion, the PL spectrum of the Zn 0.94 Er 0.02 Cr 0.04 O compound is measured at room temperature in the 370–750 nm range and excitation of 340 nm ( Figure 2 a). In Figure 2 a, two well-defined peaks are observed; the first, located in the UV region and centered at 379 nm, is typical of the near-band emission (NBE) of ZnO and is related to excitonic recombination in the band gap region (between the valence and conduction bands), and the second wide peak in the visible region that is centered at 635 nm is characteristic of intrinsic defects of the lattice [ 46 , 47 , 48 , 49 , 50 , 51 ]. The form of the peak located in the visible region confirms the degree of point defects that emerge in the compound due to the dopant’s inclusion, synthesis route, pH, annealing temperature, etc.…”

Section: Resultsmentioning

confidence: 99%

Photoresponsive Activity of the Zn0.94Er0.02Cr0.04O Compound with Hemisphere-like Structure Obtained by Co-Precipitation

et al. 2023

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In this work, a ZnO hemisphere-like structure co-doped with Er and Cr was obtained by the co-precipitation method for photocatalytic applications. The dopant’s effect on the ZnO lattice was investigated using X-ray diffraction, Raman, photoluminescence, UV-Vis and scanning electron microscopy/energy dispersive spectroscopy techniques. The photocatalytic response of the material was analyzed using methylene blue (MB) as the model pollutant under UV irradiation. The wurtzite structure of the Zn0.94Er0.02Cr0.04O compound presented distortions in the lattice due to the difference between the ionic radii of the Cr3+, Er3+ and Zn2+ cations. Oxygen vacancy defects were predominant, and the energy competition of the dopants interfered in the band gap energy of the material. In the photocatalytic test, the MB degradation rate was 42.3%. However, using optimized H2O2 concentration, the dye removal capacity reached 90.1%. Inhibitor tests showed that •OH radicals were the main species involved in MB degradation that occurred without the formation of toxic intermediates, as demonstrated in the ecotoxicity assays in Artemia salina. In short, the co-doping with Er and Cr proved to be an efficient strategy to obtain new materials for environmental remediation.

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“…All doped samples have diffraction peaks similar to wurtzite hexagonal phase (JCPDS card number 36–1451). [ 25 ] Few more peaks around 27.46° and 29.42° are found for the GZO sample, which have been attributed to the (111) and (222) planes of Gd 2 O 3 (JCPDS card no. 43–1015).…”

Section: Resultsmentioning

confidence: 99%

“…Two transitions—the first from the

Zn_{\rm{i}}^ +

{\rm{V}}_{\rm{O}}^ *

to the

{\rm{V}}_{\rm{O}}^ +

and the second from the CB to the

{\rm{V}}_{\rm{O}}^ +

—are most likely which are accountable for the peak at 630 nm. [ 56 ] For all samples of undoped ZnO and GZO nanoparticles, the NIR emission peak appears at 766 nm (1.64 eV). As the dopant concentration increases, NIR emission peak intensity in Figure 11 decreases monotonically.…”

Section: Resultsmentioning

confidence: 99%

Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd³⁺‐Substituted ZnO Nanoparticles

Sahu

Kumar

Vats

et al. 2022

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of ZnO has not yet been completely realized and explored despite two decades of rigorous research. It has a wide range of uses in photocatalysts, UV lasers, solar cells, photodiodes, sensors, optoelectronics, spintronic devices, and more. [1][2][3][4][5][6] Depending on the application, essential modifications have been made over time to increase the stability of ZnO nanostructures. High quantum confinement effect plays a significant role in the configuration of the electronic structure at the nanoscale. Also, factors such as doping, defects, and crystallinity affect various properties of the nanostructures. Doping ZnO with appropriate ions with varying sizes is great approach way to vary its properties for certain device applications. [7][8][9] According to Chaudhary et al., WO 3 -ZnO@rGO nanocomposites can be used for relevant photocatalytic applications and wastewater purification. [10] Additionally, Yousaf et al. have reported that the ZnO-NiO/rGO nanohybrid shows exceptional photocatalytic performance and is a reliable contender in the field of catalysis. [11] Transition metal (TM) and rare earth (RE)-doped metal oxides have been studied extensively under this regime. For optoelectronics and spintronic applications, ZnO doped with rare-earth ions is Undoped ZnO and Zn 1−x Gd x O nanoparticles are made using a sono-chemical co-precipitation approach. X-ray diffraction and transmission electron microscopy investigations verified the formation of a wurtzite structure with spherical geometry. All the samples are found to be nanocrystalline by transmission electron microscopy, with crystallite diameters ranging from 14 to 22 nm. The optical constants are calculated via diffuse reflectance spectroscopy. The Urbach energy and photoluminescence spectrum both showed that all doped nanoparticle samples contained defects and disorder due to vacancies. The band structure finding suggest that the forbidden gap of ZnO may change due to the conduction band shift, Burstein-Moss shift, and shrinkage effect. The near band emission in the ultraviolet region and deep level emission of the photoluminescence spectrum are both strong and decreased with increasing Gd 3+ concentration. Studies using X-ray absorption near edge spectroscopy revealed that the host nano-lattice Zn sites are substituted with Gd 3+ cations to preserve the symmetry with minor distortion. Investigations into charge transfer through the oxygen bands (Gd-O-Zn) are made using O K-edge spectra. The defect emission bands identified through Gd doping indicated that these emissions may be changed for ZnO samples, which could be advantageous for applications in phosphors and light-emitting devices.

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A comprehensive study on the impact of Gd substitution on structural, optical and magnetic properties of ZnO nanocrystals

Cited by 67 publications

References 96 publications

Design of various Ni–Cr nanostructures and deducing their magnetic anisotropy

Design of various Ni–Cr nanostructures and deducing their magnetic anisotropy

Photoresponsive Activity of the Zn0.94Er0.02Cr0.04O Compound with Hemisphere-like Structure Obtained by Co-Precipitation

Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd³⁺‐Substituted ZnO Nanoparticles

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A comprehensive study on the impact of Gd substitution on structural, optical and magnetic properties of ZnO nanocrystals

Cited by 67 publications

References 96 publications

Design of various Ni–Cr nanostructures and deducing their magnetic anisotropy

Design of various Ni–Cr nanostructures and deducing their magnetic anisotropy

Photoresponsive Activity of the Zn0.94Er0.02Cr0.04O Compound with Hemisphere-like Structure Obtained by Co-Precipitation

Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd3+‐Substituted ZnO Nanoparticles

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Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd³⁺‐Substituted ZnO Nanoparticles