Review on structure, optical and magnetic properties of cobalt doped ZnO nanoparticles

Nayak, Sourav; Kumar, Pawan

doi:10.1016/j.matpr.2023.01.318

Cited by 7 publications

(4 citation statements)

References 31 publications

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“…In our research design, we selected cobalt as the metal dopant for zinc oxide (ZnO) due to its enhanced optical properties, such as a red shift caused by a reduced band gap, as documented in the literature. An additional study corroborated our methodology, suggesting that there is a positive correlation between the concentration of cobalt in ZnO and the absorption of UV rays [27,28]. In contrast, our inquiry was concentrated on the doping of ZnO with 3% cobalt, which is consistent with a recent study by S. Vinoth et al [29] demonstrating the tendency for 3% cobalt to increase UV-ray absorption.…”

Section: Introductionsupporting

confidence: 91%

Incorporation of zinc oxide and cobalt doped zinc oxide nano-rods in commercial sunscreen sample to optimize its UV-ray absorption

Ansari,

Riaz,

Gull

et al. 2024

Phys. Scr.

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In the last two decades, the ozone layer in the atmosphere has beendepleted, and the sun rays are now more harmful to human skin becausethey no longer filters it completely. Long-term exposure to harmfulultraviolet rays (UV-rays), which have wavelengths between 220nm and380nm, causes catastrophic damage to skin cells. Sunscreens aretherefore absolutely necessary to protect the skin. The co-precipitationmethod was used to synthesize both pure and cobalt-doped zinc oxidenano structures. In sunscreens, these nanostructures serve as a UV filter.The obtained nano structures have been characterized by X-raydiffraction (XRD), scanning electron microscopy (SEM), and diffusereflectance spectroscopy (DRS). The ability of a sunscreen samplecontaining nano structures to yield results for a period of various hours a tdifferent temperatures (20°C, 30°C, and 50°C) has been tested.According to XRD results, prepared samples exhibits hexagonal wurtzitecrystalline structures and are of 22nm in size for pure zinc oxide and 20nmin size for cobalt-doped zinc oxide. SEM was used to find morphologies,i.e., nano rods (NRs) at 200nm and 2µm. DRS provided evidence ofsunscreen's endurance, with a 97% absorption of UV-rays at 50°C for upto 6 hours when incorporated with NRs. In order to boost UV-rayabsorption in sunscreen, nanotechnology has been successfully applied.

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Section: Introductionsupporting

confidence: 91%

Incorporation of zinc oxide and cobalt doped zinc oxide nano-rods in commercial sunscreen sample to optimize its UV-ray absorption

Ansari,

Riaz,

Gull

et al. 2024

Phys. Scr.

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“…It was noted that the largest narrowing of the band gap down to 3.13 eV was observed in ZnO containing 5 wt.% of cobalt. It was demonstrated that an oxide p-n junction of the Co 3 O 4 /ZnO can operate as a photodetector in the visible light range [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Nanocomposite Co3O4-ZnO Thin Films for Photoconductivity Sensors

Petrov

Sysoev

Ignatieva

et al. 2023

Sensors

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Thin nanocomposite films based on zinc oxide (ZnO) added with cobalt oxide (Co3O4) were synthesized by solid-phase pyrolysis. According to XRD, the films consist of a ZnO wurtzite phase and a cubic structure of Co3O4 spinel. The crystallite sizes in the films increased from 18 nm to 24 nm with growing annealing temperature and Co3O4 concentration. Optical and X-ray photoelectron spectroscopy data revealed that enhancing the Co3O4 concentration leads to a change in the optical absorption spectrum and the appearance of allowed transitions in the material. Electrophysical measurements showed that Co3O4-ZnO films have a resistivity up to 3 × 104 Ohm∙cm and a semiconductor conductivity close to intrinsic. With advancing the Co3O4 concentration, the mobility of the charge carriers was found to increase by almost four times. The photosensors based on the 10Co-90Zn film exhibited a maximum normalized photoresponse when exposed to radiation with wavelengths of 400 nm and 660 nm. It was found that the same film has a minimum response time of ca. 26.2 ms upon exposure to radiation of 660 nm wavelength. The photosensors based on the 3Co-97Zn film have a minimum response time of ca. 58.3 ms versus the radiation of 400 nm wavelength. Thus, the Co3O4 content was found to be an effective impurity to tune the photosensitivity of radiation sensors based on Co3O4-ZnO films in the wavelength range of 400–660 nm.

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“…For example, cobalt (Co) doping can lead to distortion of the ZnO lattice and, when exceeding the Co solubility limit, can lead to cluster formation and the generation of metastable phases such as a ZnO-CoO, where Co 2+ ions replace Zn 2+ ions. Depending on the synthesis methodology, this can make it possible to obtain phase separation in spinel-type compounds, e.g., ZnO, CoO, and Co 3 O 4 [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Cobalt Doping Effects in Zinc Oxide: A Combined Experimental and Ab Initio Approach

Pereira,

Ferreira,

Correa

et al. 2023

Crystals

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In this paper, we investigate the solubility effects of Co in ZnO (Zn1−xCoxO, where x = 0, 0.03, 0.05, 0.1, 0.2, 0.25, 0.4, 0.8, and 1) by combining the results of perturbed angular correlation (PAC) spectroscopy using highly diluted 111Cd as probe nuclei and ab initio calculations based on spin-density functional theory (SDFT). This combined approach enables us to characterize the local structure around Cd ions, where, through PAC technique, it was possible to measure the EFG as a function of temperature and Co concentration and thereby monitor the changes in the structure and the Co solubility threshold in ZnO and the ZnO/CoO/Co3O4 mixed phase. The full-potential linear augmented plane wave plus local orbital (APW+lo) formalism were used here to describe the electronic structure of the supercells, including the atomic relaxations. These Ab initio calculations show an interesting behavior of the Cd and Co impurity levels in the band structure of ZnO, which explains the experimental results in terms of the origin of EFG and the evidence of ferromagnetic response.

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Review on structure, optical and magnetic properties of cobalt doped ZnO nanoparticles

Cited by 7 publications

References 31 publications

Incorporation of zinc oxide and cobalt doped zinc oxide nano-rods in commercial sunscreen sample to optimize its UV-ray absorption

Incorporation of zinc oxide and cobalt doped zinc oxide nano-rods in commercial sunscreen sample to optimize its UV-ray absorption

Nanocomposite Co3O4-ZnO Thin Films for Photoconductivity Sensors

Cobalt Doping Effects in Zinc Oxide: A Combined Experimental and Ab Initio Approach

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