Bright Red Luminescence and Structural Properties of Eu<sup>3+</sup> Ion Doped ZnO by Solution Combustion Technique

Abstract

Pure, and Europium ion doped Zinc oxide nanocrystals (ZnO:Eu 3+ ) were synthesized by a solution combustion technique. The X-ray diffraction patterns (XRD) reveals the existence of the Eu 2 O 3 phase. From the results of both, X-ray diffraction and photoluminescence spectra (PL) reveal that Eu 3+ ions successfully substitute for Zn 2+ ions in the ZnO lattice, moreover, when the amount of doped Europium was varied, this changes are showed in changes in the luminescence intensity. The PL is broad and a set of colors was emitted which originates from ZnO and the intra 4f transitions of Eu 3+ ions. The existence of the Zn-O, Eu 3+ -O and O1s bonding energies were confirmed by X-ray photoelectron spectroscopy (XPS) technique. The samples morphology was registered by a scanning electron microscopy (SEM) technique, and reveals that Europium ions are present on the surface of the ZnO nanocrystals.

Fast, Low-Cost Synthesis of ZnO:Eu Nanosponges and the Nature of Ln Doping in ZnO

“…The latter shoulder peak is broad and might be composed of several components in spite of the very good fit when using one peak component. This peak is sometimes also connected to defects, such as oxygen vacancies, showing a peak appearing in the lower-BE part of this oxygen peak. ,,,,,,,,− ,,− It might also contain a component of carboxylate or carbonate oxygen with a slightly higher BE of 531.6 eV, found for the Eu–oxo-carbonate, as indicated by its IR spectrum . Yet, a minor component of it could fit within the high-BE side of the broad 531.33 eV peak.…”

“…In the Eu 3d region, the ZnO:5%Eu sample showed two sets of peaks around 1134 and 1164 eV, corresponding to photoemission from the Eu 3d 5/2 and Eu 3d 3/2 levels, respectively. ,− ,,,,,,,,,,,− The Eu 3d 5/2 core level peaks can be seen as consisting of three groups with peak components at (i) 1124.30 (1.62) and 1126.44 (1.37), (ii) 1131.66 sh (6.38), 1134.34 (76.99), and 1136.84 sh (8.87), and (iii) 1142.87 (4.77) eV. Following the prevailing assignments in the literature, the first group of peak components on the low-energy side are associated with Eu 2+ , while the second group of peaks are associated with Eu 3+ . ,,, These BE values correspond well with the literature values for europium oxides. ,,,,,,,,− ,,− , The satellite peak at 1142.87 eV is associated with shake-down processes. , …”

“…Regarding Eu-doped ZnO, there is a large variety of structures reported, including thin films, rods/wires, sea urchins, cauliflower-like balls, and powders, achieved by a wide range of chemical and physical synthesis routes, including radio frequency sputtering, − pulsed laser deposition, ion implantion, , chemical vapor deposition, vapor transport deposition, ,− spray pyrolysis, , solid-state synthesis, ,, electrochemical synthesis, − combustion synthesis, − precipitation and hydro-/solvothermal synthesis, − hydrothermal microemulsion processing, sonochemically assisted precipitation, chemical solution deposition, − and metal–organic decomposition . A more detailed review of the results given in these references is provided in Review S1.…”

Quenching Photoluminescence of Eu(III) by Cu(II) in ZnO:Eu3++Cu2+ Compounds by Solution Combustion Method

“…The Figure 4(a) and Figure 4(b) shows the room temperature photoluminescence spectra (PL) of the Eu 3+ doped ZnO without the Cu 2+ ion dopant and of the Cu 2+ +Eu 3+ doped ZnO (ZnO:Cu 2+ +Eu 3+ ) nanocrystals as a function of the Cu 2+ ion concentration in Wt% and after both samples undoped and doped with the Cu 2+ were annealing at 900˚C by 24 h, the samples were irradiated with an excitation wavelength of 270 nm (in the UV range). In Figure 4(a) it is observed that the PL spectra correspond to the Eu 3+ ion emission in a ZnO matrix, in particular the most intense peak at the visible color red whit 613 nm in wavelength [27]. However it is observed from Figure 4(b) that the ZnO:Cu 2+ +Eu 3+ samples doped with 1, 2, 3, 10, and 20 Wt% are all alike: because they does not present antypical green broad emission band from 400 nm to 600 nm centered about 516 nm [28] as is showed in Figure 4(a), this band is due to the intrinsic defects emission of ZnO host.…”

“…The introduction of Cu 2+ ions into ZnO lattice sums or produces changes that improve the ZnO properties such as: band gap tailored, magnetic and electrical properties, passivation of defects, as p-type dopant in the original n-type ZnO semiconductor. However, actually it is well known that the co-doping with Cu 2+ ion in Eu 3+ doped glasses photoluminescent compounds the Cu 2+ ion can quench the Eu 3+ photoluminescence [27]- [29] with the increase of the Cu 2+ ion concentration in glasses matrix; this quenching effect can be used to tuning between ultra-violet and visible emission in devise photoluminescent. In this study co-doped ZnO/Cu 2+ + Eu 3+ solid solution powders have been synthesized by solution combustion method as a function of the Cu 2+ ion concentration in %Wt.…”