Synthesis and photoluminescent properties of Y₂O₃:Eu³⁺ thin films prepared from F127-containing solution

Abstract

Dense and transparent Y 2 O 3 :Eu 3+ films were prepared by the solgel process and dip-coating technique from an yttrium 24 pentanedionate, europium nitrate and a methanol solution modified with F127 pluronic acid, by incorporation of acetic acid as pH modifier and acetylacetone as sol stabilizer. It was evaluated the effect of the F127/Y molar relationship (0, 0.1, 0.2, 1.0, 1.2 and 5.0) on the structure and photoluminiscent properties of the derived thin films. After 3 dipping-cycles, XRD results showed that the F127-modified films began to crystallize at 600°C into the cubic structure, and from 800°C, was found that the presence of F127 changes the preferential orientation from a ©100ª orientation, for the non-modified sample, to a ©111ª orientation, for the modified ones. M-lines spectroscopy characterization showed that the maximum thickness of the films modified and annealed at 900°C was 1937 nm (µ = 4.87 g cm ¹3, © = 1.887), compared with the 881 nm (µ = 4.94 g cm ¹3, © = 1.907) for a non-modified sample. Differential thermal analysis (DTA) and infrared spectroscopy (FTIR) were carried out to evaluate the chemical and structural evolution of the xerogel formed during the annealing process. AFM micrographs showed smooth crack-free surface (Ra = 9.2 nm) on a F127/Y = 0.2 sample. Finally, the films presented a typical Eu 3+ reddish emission at 611 nm (D o ¼ 7 F 2 ), which was analyzed as function of the F127 pluronic content and the annealing temperature.

Luminescence Properties and Energy Transfer of Eu3+, Bi3+ Co-Doped LuVO4 Films Modified with Pluronic F-127 Obtained by Sol–Gel

“…Most luminescent materials are usually oxides, sulfides, or oxysulfides doped with some transition metal or rare-earth element [6][7][8], but in recent years, some lanthanides known as orthovanadates are currently used as matrices due to their high emission efficiency [9][10][11][12]. Additionally, these materials have unique properties due to the stoichiometric combination of their components and their symmetry with the crystal of the complex oxides; these characteristics increase the luminescent activity in comparison with the simple materials [13][14][15][16][17][18]. Likewise, rare-earth ions that are used as impurities in orthovanadates have shown strong emissions as well as variations in the emission color corresponding to the different activating ions under the excitation of an electron beam or ultraviolet.…”