Efficient multicolor tunability of ultrasmall ternary-doped LaF₃ nanoparticles: energy conversion and magnetic behavior

Abstract

Luminescence-tunable multicolored LaF:xCe,xGd,yEu (x = 5; y = 1, 5, 10, and 15 mol%) nanoparticles have been synthesized via a low cost polyol method. Powder X-ray diffraction and high-resolution transmission electron microscopy studies confirm the hexagonal phase of the LaF:xCe,xGd,yEu nanophosphors with average sizes (oval shape) ranging from 5 to 7 nm. Energy-dispersive X-ray spectroscopy analyses show the uniform distribution of Ce, Gd, and Eu dopants in the LaF host matrix. The photoluminescence spectra and electron paramagnetic resonance measurements guarantee the presence of Eu, corroborated through DC susceptibility measurements of the samples displaying paramagnetic behavior at 300 K, whereas weak ferromagnetic ordering is shown at 2 K. The non-radiative energy transfer processes from the 4f(F) → 5d state (Ce) to the intraconfigurational 4f excited levels of rare earth ions and simultaneous emissions in the visible region from the 4f5d (Eu) and D (Eu) emitting levels, leading to overlapped broad and narrow emission bands, have been proclaimed. The energy transfer mechanism proposes involvement of the Gd ion sub-lattice as the bridge and finally trapping by Eu, upon excitation of the Ce ion. The calculation of experimental intensity parameters (Ω) has been discussed and the highest emission quantum efficiency (η = 85%) of the Eu ion for the y = 10 mol% sample is reported. The advantageous existence of the Eu/Eu ratio along with variously doped nanomaterials described in this work, results in tunable emission color in the blue-white-red regions, highlighting the potential application of the samples in solid-state lighting devices, scintillation devices, and multiplex detection.

Energy Transfer Study on Tb3+/Eu3+ Co-Activated Sol-Gel Glass-Ceramic Materials Containing MF3 (M = Y, La) Nanocrystals for NUV Optoelectronic Devices

“…It is very interesting that the φ Eu value for SiO 2 -YF 3 :Tb 3+ ,Eu 3+ is in good accordance with the presented data, but the SiO 2 -LaF 3 :Tb 3+ ,Eu 3+ GC sample is characterized by a greater quantum efficiency value. Furthermore, as was proven by N. Shrivastava et al [66], the quantum yields for LaF 3 :Eu 3+ nanocrystals could vary from 67% up to 85% depending on the Eu 3+ concentration. Therefore, the obtained results suggest that fabricated sol-gel glass-ceramics could be considered as quite good candidates for visible light-emitting devices.…”

Red‐Emitting Magnetic Nanocomposites Assembled from Ag‐Decorated Fe3O4@SiO2 and Y2O3:Eu3+: Impact of Iron‐Oxide/Silver Nanoparticles on Eu3+ Emission

“…The bifunctional nanomaterials with magnetically responsive core and optical shell have been attracted broad research interest since last several decades . These features are due to their well‐defined structures that co‐assemble the respective properties of each component in single particles with cooperatively enhanced performances .…”

“…Therefore, these composite materials have been demonstrated great potential in wide range of multimodal biomedical applications, for example, drug delivery carriers, photothermal destruction of tumor cells,, multimodal MRI contrast agents, quantitative DNA analyses and magnetic hyperthermia for cancer therapies ,. The luminescent and magnetic nanomaterials can be obtained by coating or layer‐by‐layer deposition of rare earth phosphors,,, quantum dots on magnetic core nanoparticles, polymers assisted encapsulation or co‐assembling of magnetic nanoparticles and luminophores in single nanostructures, as well as functionalization of Fe 3 O 4 with dyes or luminescence rare earth complexes ,…”

Controllable synthesis of glass ceramics containing YF3:Eu3+ nanocrystals: Well‐preserved Eu and prolonged lifetime

“…Among them, YF 3 NCs with low phonon energy (360 cm −1 ), wide bandgap and comparable ion size of Y with Eu + ion, has aroused considerable attention as host matrix of Eu 3+ . Eu 3+ ‐doped YF 3 fluorescent materials present excellent red emitting and hold the potential to be widely used in display devices, optical data storage, and optical communication . However, the aging issue and short light emitting lifetime caused by the poor thermal stability of fluoride hosts limit their applications in photonic device.…”

“…Eu 3+ -doped YF 3 fluorescent materials present excellent red emitting and hold the potential to be widely used in display devices, optical data storage, and optical communication. [5][6][7][8][9][10] However, the aging issue and short light emitting lifetime caused by the poor thermal stability of fluoride hosts limit their applications in photonic device.…”