FLUORESCENCE QUANTUM YIELD OF Yb3+-DOPED TELLURITE GLASSES
ANA KELY RUFINO SOUZA1; ANA PAULA LANGARO1; JUNIOR REIS SILVA1; FRANCINE BETTIO
COSTA1; JOÃO CARLOS SILOS MORAES2; MÁRCIO DA SILVA FIGUEIREDO3; FÁBIO ALENCAR
SANTOS3; MAURO LUCIANO BAESSO4; LUIZ ANTÔNIO DE OLIVEIRA NUNES5; LUIS HUMBERTO DA
CUNHA ANDRADE1; SANDRO MARCIO LIMA1
1Universidade
Estadual de Mato Grosso do Sul, C.P. 351, 79804-970, Dourados, MS.
de Vidros e Cerâmicas, Universidade Estadual Paulista, C.P. 31, 15385-000, Ilha Solteira, SP.
3Universidade Federal da Grande Dourados, C.P. 364, 79804-970, Dourados, MS.
4Universidade Estadual de Maringá, 87020-900, Maringá, PR.
5Laboratório de Laser e Aplicações, Universidade do Estado de São Paulo, C.P. 369, 13560-970, São
Carlos, SP.
2Grupo
Introduction: The energy transfer from a sensitizer ion to an activator has been investigated aiming to
minimize losses and the increase in efficiency of energy conversion in solar cells. The high-energy photons
(UV-Vis) absorbed by the sensitizer are converted to photons of low energy by means of the downconversion
(DC) mechanism [1]. This phenomenon has been extensively investigated due to its radiative 2F5/2 → 2F7/2
transition that overlaps with the energy band gap of silicon semiconductors. In order to investigate the Yb3+
characteristics as an activator, it is strongly important to know its fluorescence quantum yield (η), which
measures the conversion of absorbed photons into emitted photons. Aim: To determine a precise η value for
the Yb-doped tellurite TL and TW (Tellurium-lithium; Tellurium-Tungsten, respectively) glasses sets, by using
the thermal lens spectroscopy (TLS) technique in different procedures. Material and methods: Firstly, η was
determined by using the conventional method in which a reference sample (undoped, ηref) is used; secondly,
the TLS was applied in the multiwavelength (ηmulti) form, in which no reference sample is required; after that,
the TLS was normalized by the lifetime for η measurements (ηnorm). Results and discussion: The average
values (among ηnorm, ηref and ηmulti values) of η for TL and TW glasses in function of the Yb concentration are
plotted in Figure 1. As noted, the values are higher than 90% of the lowest Yb concentration. The value
found for concentrations < 2x1020 ions/cm3 of Yb3+ in TL glass is relatively higher than those values found by
authors others [2] using the same TLS in other Yb3+-doped tellurite glasses. Conclusions: In conclusion, our
results show that within of the experimental limitation of each TLS procedure, it is possible to affirm that was
effective in determining the quantum efficiency for the ions of Yb3+ in TL and TW tellurite glasses.
Fluorescence quantum yield ( % )
1,0
TW glass
TL glass
0,9
0,8
0,7
0,6
0,5
0
2
4
6
8
10
12
14
16
Yb concentration ( 1020 ions/cm3 )
Figure 1: Average fluorescence quantum yield for TL and TW glasses in function of the Yb
concentration.
References:
[1] P. Vergeer, T.J.H. Vlugt, M.H.F. Kox, M.I. den Hertog, J.P.J.M. van der Eerden, A. Meijerink, Phys. Rev.
B 71 (2005) 014119.
[2] L.R.P. Kassab, R.A. Kobayashi, M.J.V. Bell, A.P. Carmo, T. Catunda, J Phys D Appl Phys 40 (2007)
4073.
Keywords: Fluorescence quantum efficient; downconversion; thermal lens spectroscopy.
Financial support: FUNDECT/MS.
Promoção/Realização:
Apoio: