Eu3+-doped SiO2-Gd2O3 prepared by the sol-gel
process: Structural and optical properties
Leonardo Alves Rochaa, Marco Antonio Schiavona, Sidney José L. Ribeirob,
Rogéria Rocha Gonçalvesc and Jefferson Luis Ferraria,*
a –Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais,
Universidade Federal de São João Del Rei, Campus Dom Bosco, 36301-160, São João Del Rei,
MG, Brazil
b - Instituto de Química, UNESP, P.O. Box 355, 14800-970, Araraquara, SP, Brazil
c - Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, USP –
Av. Bandeirantes, 3900, Ribeirão Preto/SP, 14040-901, Brazil
*Prof. Dr. Jefferson Luis Ferrari
Grupo de Pesquisa em Química de Materiais (GPQM)
Universidade Federal de São João del-Rei
Departamento de Ciências Naturais, Campus Dom Bosco
Praça Dom Helvécio, 74 - Fábricas
São João del-Rei – MG, Brazil
Tel (Fax): +55-32-3379-2481
e-mail address: ferrari@ufsj.edu.br and jeffersonferrari@gmail.com
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Figure
Figure S1 – TGA/DTA analysis of 0.2 mol% of Eu3+-doped xerogels with ratio between Si4+:Gd3+
of A) 30:70, B) 50:50 and C) 70:30 mol%. Figure S1 shows the analysis DTA/TGA for xerogels
containing 30 [Fig. S1 (A)], 50 [Fig. S1 (B)] and 70 mol% [Fig. S1 (C)] of Gd3+, and all
compositions present similar behavior when compared to the xerogel with 100 mol% of Gd3+, with
five steps and 45 to 50% of mass loss.
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Figure S2 – FTIR spectra for all materials obtained at 900, 1000 e 1100 ºC heated-treated for 8h.
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Table S3. The Infrared wavenumbers and vibration band assignments.
Band
Band positions (cm-1)
Band assignments
A
410
Gd-O stretching [1]
B
470
Si-O-Si deformation [2]
C
540
Gd-O stretching [1]
D
800
Si-O-Si symmetric stretching [3-5]
E
1079
Si-O-Si asymmetric stretching [3-5]
F
~3433
OH stretching [3-5]
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Figure S4 – SEM images of Eu3+-doped materials with ratio between Si4+:Gd3+ of (A) 100:0, (B)
30:70, (C) 50:50, (D) 70:30 and (E) 0:100 mol% heated-treated at 1000 °C for 8h. By the SEM
analysis it was observed that the material mainly composed by silica [Fig. S4 (A)], and it is formed
by particles with sizes on the order of micrometers, and a few plates. These plates can be related to
the sintering process of the particles. The photomicrograph of the materials based on the Eu3+doped Gd2O3 [Fig. S4 (E)] showed the formation of particles of the order of nanometers. The
materials with 30 [Fig. S4 (B)], 50 [Fig. S4 (C)] and 70 mol% [Fig. S4 (D)] of Gd3+ in the
composition are composed by particles with intermediate shapes between materials containing only
SiO2 and Gd2O3.
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Figure S5 – EDX spectra of Eu3+-doped materials with ratio between Si4+:Gd3+ of (A) 100:0, (B)
30:70, (C) 50:50, (D) 70:30 and (E) 0:100 mol% heated-treated at 1000 °C for 8h. The decrease of
the intensity of Si band located at about 1.7 KeV is clearly observed with the increase of Gd3+. It
was also observed that the presence of bands around 0.8, 1.1 and 5.6 keV in all spectra, are
attributed to the Eu3+, indicating the presence of RE3+ in all materials obtained.
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Table S6. EDX quantitative analysis of the Gd3+ and Si4+ compositions.
Samples
Nominal quantities of
Temperature (ºC)
Gd3+ (mol%)
1000
0
1000
30
1000
50
1000
70
1000
100
EDX analysis
Silicon
(mol%)
100
69.13
49.61
30.59
0
Gadolinium
(mol%)
0
30.87
50.39
69.41
100
The Table S6 shows that the compositions of the materials are in accordance to the stoichiometry
proposed.
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References:
[1] N. Dhananjaya, H. Nagabhushana, B. M. Nagabhushana, B. Rudraswamy, C. Shivakumara and
R. P. S. Chakradhar (2012) Spherical and rod-like Gd2O3:Eu3+ nanophosphors—Structural and
luminescent properties. Bull. Mater. Sci. 35:519–527.
[2] T. Liu, Y. Wang, H. Qin, X. Bai, B. Dong, L. Sun and H. Song (2011) Gd2O3:Eu3+ mesoporous
SiO2 bifunctional core–shell composites: Fluorescence label and drug release. Mater. Res. Bull.
46:2296–2303.
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reflection spectroscopy.J. Non-Cryst. Solids121:193-197.
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spectroscopy.J. Appl. Phys.58:4225-4232.
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