A comparative study on the influence of monovalent, divalent and trivalent doping on the structural, optical and photoluminescence properties of Zn0.96T0.04O (T: Li+, Ca2+&amp; Gd3+) nanoparticles

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

doi:10.1016/j.ceramint.2019.04.048

Cited by 52 publications

(8 citation statements)

References 51 publications

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“…In addition, other defects that appear in the sample, but in lower concentrations, are oxygen interstitial (O i (14%)) and zinc vacancy (V Zn (4%)). Similar results have been reported in the literature for rare earth and transition metal-doped ZnO compounds [ 46 , 47 , 48 , 49 , 50 , 51 ]. On the other hand, the UV–Vis diffuse reflectance spectrum of the Zn 0.94 Er 0.02 Cr 0.04 O compound is shown in Figure 2 c. We can see three defined bands at 487, 521 and 650 nm, which certify the replacement of Zn cations by Er cations in the ZnO crystal structure.…”

Section: Resultssupporting

confidence: 90%

“…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%

“…To quantify the point defects present in the hexagonal structure after the Er and Cr cations’ inclusion, the PL spectrum is deconvolved using a Gaussian distribution function. The defects of V o are related to the origin of green emission; in addition, it has been shown that V Zn also contributes to broadband emission in the green region [ 46 , 52 , 53 ]. In our sample, the green emission centered at ~510.9 nm (2.43 eV) corresponds to V Zn .…”

Section: Resultsmentioning

confidence: 99%

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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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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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

et al. 2023

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“…Two transitions-the first from the i Zn + or V O * to the V O + and the second from the CB to the V 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: Analysis Of Defect Structurementioning

confidence: 94%

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

Sahu

Kumar

Vats

et al. 2022

Part & Part Syst Charact

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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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“…It is slightly lowered after annealing in the visible region and undergoes significant reduction as the IR region is approached. Figures 2(b) and (c) show the plots of α 1/2 and α 2 for indirect and direct bandgap extraction, respectively [26][27][28][29][30]. A primary indirect gap of 1.56 eV is observed before annealing.…”

Section: Absorption Coefficient Bandgap and Urbach Tail Extractionmentioning

confidence: 98%

Effect of nitrogen annealing on the optoelectronic properties of manganese vanadate

Ravindra¹,

Chaudhary²,

Athresh³

et al. 2021

Semicond. Sci. Technol.

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Semiconducting oxides are often stable, non-toxic, and can potentially be deposited at a low cost. The existence of oxides with appropriate bandgap (<1.8 eV) and reasonable mobility points towards the alluring possibility of employing oxides as absorbers in ‘all-oxide’ solar cells. However, oxide absorbers have remained elusive due to the debilitating effects of low mobility, deep-defects, and inefficient doping, which degrade their optoelectronic performance. In this work, we report the effects of annealing on the optoelectronic properties of an emerging oxide solar absorber, manganese vanadate (Mn2V2O7, MVO). Films deposited using pulsed laser deposition show no photoluminescence (PL). After annealing in a nitrogen ambience, sharp PL (FWHM ∼ 100 µeV) peaks are observed at low temperatures, which indicates improved optoelectronic quality. Our analysis suggests these emissions are from carriers trapped in very shallow native acceptor and donor type defects. This improvement is correlated with the reduction in Urbach energy, which also suggests reduced electronic disorder. Coupled with low bandgap and easy processing, MVO seems to be an exciting material for optoelectronics and photovoltaics.

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A comparative study on the influence of monovalent, divalent and trivalent doping on the structural, optical and photoluminescence properties of Zn0.96T0.04O (T: Li+, Ca2+& Gd3+) nanoparticles

Cited by 52 publications

References 51 publications

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

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

Effect of nitrogen annealing on the optoelectronic properties of manganese vanadate

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A comparative study on the influence of monovalent, divalent and trivalent doping on the structural, optical and photoluminescence properties of Zn0.96T0.04O (T: Li+, Ca2+& Gd3+) nanoparticles

Cited by 52 publications

References 51 publications

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

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

Effect of nitrogen annealing on the optoelectronic properties of manganese vanadate

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