SrAl₂O₄:Eu²⁺(,Dy³⁺) Nanosized Particles: Synthesis and Interpretation of Temperature-Dependent Optical Properties

Abstract

SrAl2O4nanosized particles (NPs) undoped as well as doped with Eu2+and Dy3+were prepared by combustion synthesis for the discussion of their intensively debated spectroscopic properties. Emission spectra of SrAl2O4:Eu2+(,Dy3+) NPs are composed by a green band at 19 230 cm−1(520 nm) at room temperature, assigned to anomalous luminescence originated by Eu2+in this host lattice. At low temperatures, a blue emission band at 22 520 cm−1(444 nm) is observed. Contrary to most of the interpretations provided in the literature, we assign this blue emission band very reliably to a normal 4f6(7FJ)5d(t2g)→4f7(8S7/2) transition of Eu2+substituting the Sr2+sites. This can be justified by the presence of a fine structure in the excitation spectra due to the different7FJlevels (J=0⋯6) of the 4f6core. Moreover, Fano antiresonances with the6IJ(J=9/2,7/2) levels could be observed. In addition, the Stokes shifts (ΔES=1980 cm−1and 5 270 cm−1for the blue and green emission, resp.), the Huang-Rhys parameters ofS=2.5and 6, and the average phonon energies ofħω=480 cm-1and 470 cm−1coupled with the electronic states could be reliably determined.

Impact of Lanthanide Nanomaterials on Photonic Devices and Smart Applications

“…Aluminate nanophosphors are perhaps the most extensively investigated and reported luminescent materials; in particular, SrAl 2 O 4 is known to effectively stabilize divalent Eu 2+ dopants . Most of the emission peaks are in the green spectral range at 505–530 nm, which is slightly blue‐shifted in comparison with the emission of bulk phosphors.…”

Sinterização a laser do aluminato de estrôncio dopado via sol-gel modificado para aplicação como pigmento cerâmico

“…7b. Nele observam-se bandas de emissão características do Eu 2+ , em que a mais intensa localiza-se em torno de 520 nm e se refere à transição 4f 6 5d 1 g4f 7 do Eu 2+ [24]. O resultado confirmou a redução da maior parte do európio, inicialmente , já que a transição é permitida pelas regras de seleção espectroscópicas.…”

“…Fluorescência de raios X: na Tabela I é possível visualizar o resultado da análise química das fritas por fluorescência de raios X. O resultado indicou quantidades expressivas de silício, alumínio, cálcio, zinco e potássio, e quantidades menores de outros elementos. Estas concentrações estão de acordo com os resultados de análise química de fritas disponíveis na literatura [24][25][26]. A quantidade relativa de seus óxidos varia de frita para frita a depender do que se deseja na indústria, sendo que a introdução de um óxido ou retirada de outro implica em variação do ponto de fusão, diferentes temperaturas de transição vítrea (T g ) e, consequentemente, curvas de análise térmica diversas.…”

Magnetism and Afterglow United: Synthesis of Novel Double Core–Shell Eu2+‐Doped Bifunctional Nanoparticles

“…Beyond these classical applications, the joining of magnetic and luminescent properties in one single assembly represents a significant step for biotechnological and medical applications such as biosensing, bioimaging, and DNA labeling . Several examples of core–shell magnetic–fluorescent nanoparticles (NPs) have been reported previously in the literature . In general, these particles are composed of a magnetic core combined with a coating layer of luminescent material.…”