Multi-color luminescence of uniform CdWO₄nanorods through Eu³⁺ion doping

Abstract

Uniform Eu 3+ doped CdWO 4 nanorods were prepared via a simple hydrothermal method and characterized by X-ray diffraction, transmission electron microscopy, photoluminescence (PL) spectroscopy and PL lifetime measurement. The results indicate that the obtained Eu 3+ doped CdWO 4 nanorods have monoclinic phase structure, and the phase structure can be retained at Eu 3+ doping concentrations of 0.4%~4.0%. The diameter of nanorods decreases from 27 to 15 nm with an increase in the doping concentrations, and the morphology becomes irregular at the Eu 3+ doping concentration of 6.5%. Under the excitation of ultraviolet light, the relative intensities of blue-green emission ascribed to WO 4 2and red emission from Eu 3+ can be tuned through doping Eu 3+ ions into the CdWO 4 nanorods and thus altering the energy transfer between WO 4 2and Eu 3+ . Hence, the multi-color luminescence in a same host under single excited wavelength can be realized simply by altering the doping concentration of Eu 3+ . These luminescent nanomaterials may have potential applications in displays, light sources, bioimaging and so on.

Effect of annealing temperature on luminescence properties of ZnWO 4 :Eu 3+ nanophosphor

“…The excitation spectrum monitored at 614 nm shows an asymmetrical broad‐band at the range of 230–330 nm, which is corresponding to the O 2− →Eu 3+ and O 2− →W 6+ charge transfer state transitions [23, 25, 31]. Additionally, the sharp line peaked at 394 nm is assigned to the 7 F 0 – 5 L 6 transitions of Eu 3+ ions [22, 32]. Meanwhile, it is also worth noting that the ZnWO 4 :Eu 3+ phosphors exhibit a broad‐band emission centred at 489 nm, called ‘intrinsic luminescence’ and which is caused by the electron transition between the O 2p orbitals and the empty d orbitals of the central W 6+ ions in WO 4 2− groups.…”

“…Generally, using a single-phase white-light-emitting phosphor instead of phosphor blends could help to reduce some of this variability [16][17][18][19]. Under deep ultraviolet excitation, zinc tungstate (ZnWO 4 ) can exhibit a broad, intrinsic blue-green emission due to a charge transfer between oxygen and tungsten ions in the WO 4 2− groups [20][21][22][23]. When doped with Eu 3+ ions, ZnWO 4 not only emits blue-green light but also effectively transfers energy to Eu 3+ ion, generating red emissions, which becomes a potential white-light-emitting phosphor [24][25][26].…”

CT/MRI‐Guided Synergistic Radiotherapy and X‐ray Inducible Photodynamic Therapy Using Tb‐Doped Gd‐W‐Nanoscintillators

“…The contained high‐ Z elements tungsten and gadolinium endow GWOT@MC540 NPs with the potential to be dual‐modal contrast agents for both CT and MRI . As shown in Figure a,b, GWOT@MC540 NPs exhibited a stronger CT imaging ability than iohexol, with a slope of 21.1 HU mL mg −1 (GWOT@MC540) vs. 16.2 HU mL mg −1 (iohexol) .…”

“…This activates MC540 and initiates X‐PDT, while the contained high‐ Z elements can spontaneously interact with X‐rays as radiosensitizers to enhance the RT efficiency, thus achieving synergistic RT&X‐PDT. Meanwhile, the GWO matrix is endowed with a dual‐modal imaging capacity, as Gd 3+ ‐based contrast agents for MRI have been shown to greatly improve the accuracy of diagnosis due to their high r 1 value, while it has already been demonstrated that W‐based contrast agents have great potential for CT . To the best of our knowledge, there is no report on GWO‐based nanoscintillators that have been designed as multifunctional nanoagents for cancer theranostics.…”

Multifunctional pure and Eu3+ doped β-Ag2MoO4: photoluminescence, energy transfer dynamics and defect induced properties

“…It is reported that in solid-state luminescent materials where possibility of energy transfer process exists, when the host materials or sensitizers are excited (indirect excitation), some luminescence decay curves from the rare-earth activator could follow a non-exponential function [46,47]. As discussed that for Ag 2 MoO 4 :Eu 3+ phosphor, there exists significant amount of energy transfer from MoO 4 2− anionic complex to Eu 3+ excitation at 260 nm, and this is followed by the luminescence decay from the 5 D 0 level of Eu 3+ .…”