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In this study, Er³⁺ doped ZnO semiconductor quantum dots (QDs) were synthesized using a wet chemical method. The successful doping of Er³⁺ ions into the ZnO host lattice and the elemental composition was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The ZnO and Er³⁺ doped ZnO QDs with a hexagonal structure, spheri...
Citations
... Among these rare earths, erbium (Er) is an element that stands out for its magnetic, optical characteristics, but most importantly, for its non-toxicity (Ca et al., 2023;Laokae et al., 2023). ...
Pure ZnO and erbium (1, 3, and 5 at. %)-doped ZnO nanoparticles aerogels were synthesized by sol-gel in supercritical drying conditions of isopropanol. The aim of this work is to study the effect of erbium ions on structural, optical, and photocatalytic properties of ZnO aerogels using various physicochemical techniques. The photocatalytic degradation of methylene blue (MB) under UV light irradiation is significantly enhanced with the introduction of Er³⁺ ions into the structure. The complete degradation of MB (99%) was obtained with an optimum of 1 and 3 at. % of erbium after 100 min of UV irradiation. These results are in good agreement with those obtained by electron paramagnetic resonance (EPR) spectroscopy spin trapping measurements where the highest amount of hydroxyl radicals •OH, responsible for the degradation of methylene blue, is observed with ZnO doped with 1 and 3 at. % erbium. A decrease of the electron-hole pairs recombination rate was confirmed by photoluminescence (PL) analyses in the Er-doped samples, due to the high interactions between Er³⁺ ions which lead to an increase of the non-radiative process originated from PL quenching.
Graphical abstract
... Among these rare earths, erbium (Er) is an element that stands out for its magnetic, optical characteristics, but most importantly, for its non-toxicity (Ca et al., 2023;Laokae et al., 2023). ...
In this study, Er-doped CoAl2O4 nanocrystals (NCs) were synthesized via co-precipitation. All the NCs were crystallized in the form of a single phase with a spinel structure and Er³⁺ ions replaced Al³⁺ ions in the formation of the CoAl2−xErxO4 alloy structure. The optical characteristics of the Er³⁺ ion-doped CoAl2O4 NCs were thoroughly investigated by analyzing both the UV-VIS and photoluminescence spectra, using the Judd–Ofelt theory. The effect of Er doping content on the luminescent properties of the CoAl2O4 pigment (using lasers emitting at wavelengths of 413 and 978 nm) has been studied. The values of Judd–Oflet intensity parameters (Ω2, Ω4, and Ω6) were determined from the absorption spectra using the least square fitting method. The J–O parameters were calculated and compared with those of other host materials; the values of the Ω2, Ω4, and Ω6 parameters decreased with an increase in Er concentration. This suggests that the rigidity and local symmetry of the host materials become weaker as the concentration of Er³⁺ ions increases. The highest value of the Ω2 parameter, when compared with Ω4 and Ω6, suggests that the vibrational frequencies in the given samples are relatively low. The upconversion fluorescence phenomenon was observed and explained in detail under an excitation wavelength of 978 nm when the excitation power was varied.
In this study, CdTexSe1−x (0 ≤ x ≤ 1) and CdTeSe:Gd y% (y = 0–8.05) alloy semiconductor nanocrystals (NCs) were prepared by wet chemical method. The presence and composition of the elements in the sample were determined by energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS). Structural analysis of X-ray diffraction (XRD) patterns indicated that most NCs crystallized in the zinc blende (ZB) structure however some Gd-doped NCs (y = 4.52 and 8.05%) crystallized in the wurtzite (WZ) structure. The emission peak of CdTexSe1−x (0 ≤ x ≤ 1) NCs varied over a wide range when changing x while the particle size remained almost unchanged. The effect of Gd doping on the structure and optical and magnetic properties of CdTeSe NCs was studied in detail. When the Gd concentration increases from 0–8.05%: (i) the structure of CdTeSe NCs gradually changed from ZB to WZ, (ii) the emission efficiency of the material was significantly reduced, (iii) the PL lifetime of samples increased more than 10 times, and (iv) the ferromagnetic properties of the material were enhanced. The research findings demonstrated that it is possible to control the crystal structure, optical characteristics, and magnetic properties of Gd-doped CdTeSe nanocrystals by adjusting the dopant concentration and chemical composition of the host material.
