Spectrochimica Acta Part A 79 (2011) 696–700
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
jou rn al hom epa ge: www.elsevier.com/locate/saa
Rare earth-doped lead borate glasses and transparent glass–ceramics:
Structure–property relationship
W.A. Pisarski
a,∗
, J. Pisarska
a
, M. M˛ aczka
b
, R. Lisiecki
b
, L. Grobelny
a
, T. Goryczka
c
,
G. Dominiak-Dzik
b
, W. Ryba-Romanowski
b
a
Institute of Chemistry, University of Silesia, Szkolna 9, 40-007 Katowice, Poland
b
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland
c
Institute of Materials Science, University of Silesia, Bankowa 12, 40-007 Katowice, Poland
a r t i c l e i n f o
Article history:
Received 25 September 2009
Accepted 20 April 2010
Keywords:
Lead borate glasses
Glass–ceramics
Rare earth ions
Structure
Luminescence
a b s t r a c t
Correlation between structure and optical properties of rare earth ions in lead borate glasses and
glass–ceramics was evidenced by X-ray-diffraction, Raman, FT-IR and luminescence spectroscopy. The
rare earths were limited to Eu
3+
and Er
3+
ions. The observed BO
3
↔ BO
4
conversion strongly depends
on the relative PbO/B
2
O
3
ratios in glass composition, giving important contribution to the luminescence
intensities associated to
5
D
0
–
7
F
2
and
5
D
0
–
7
F
1
transitions of Eu
3+
. The near-infrared luminescence and
up-conversion spectra for Er
3+
ions in lead borate glasses before and after heat treatment were measured.
The more intense and narrowing luminescence lines suggest partial incorporation of Er
3+
ions into the
orthorhombic PbF
2
crystalline phase, which was identified using X-ray diffraction analysis.
© 2010 Elsevier B.V. All rights reserved.
1. Introduction
Lead borates belong to wide family of heavy metal glass (HMG)
materials, which are favorable to be investigated by spectroscopic
methods. The Raman and FT-IR spectroscopic techniques well
illustrate the structural changes in lead borate glass, where var-
ious borate units can exist depending on PbO concentration. On
the other hand, the introduction of heavy metal elements to the
glass matrix gives important contribution to the increasing of
radiative parameters for rare earth (Ln
3+
) ions. In a consequence,
the presence of PbO and/or PbF
2
in borate glass enhanced sig-
nificantly luminescence of Ln
3+
. The optical effects are stronger
for heat-treated oxyfluoride glass samples, where PbF
2
crystals
are formed during controlled temperature-induced crystallization
and part of Ln
3+
ions is successfully incorporated into crystalline
phase. These advantages are useful for structural and optical
investigations.
The trivalent Eu
3+
with its unsplit
7
F
0
ground state is a very
convenient spectroscopic probe of the crystal field and can provide
information related to the local structure and bonding character-
istics of different glass matrices. The ratio of integrated emission
intensity of the
5
D
0
–
7
F
2
transition to that of the
5
D
0
–
7
F
1
transition,
defined as fluorescence intensity ratio R, is relative to the strength of
∗
Corresponding author.
E-mail addresses: Wojciech.Pisarski@us.edu.pl, wpisarsk@us.edu.pl
(W.A. Pisarski).
covalent/ionic bonding between the Eu
3+
ion and the surrounding
ligands and the spectroscopic key to estimate the deviation from
the site symmetries of the Eu
3+
ions. All compositional changes
strongly influenced on the local structure around Ln
3+
. The struc-
tural changes are correlated with the luminescence measurements
associated to the
5
D
0
–
7
F
2
/
5
D
0
–
7
F
1
transitions of Eu
3+
. Moreover,
many glass systems demonstrate intense and efficient red lumines-
cence related to the
5
D
0
–
7
F
2
transition of Eu
3+
. These aspects are
well documented in the literature. Structural and optical properties
of Eu
3+
ions in lead borate glasses and glass–ceramics are previously
reported [1–3]. In contrast to Eu
3+
, the trivalent erbium are the
most popular and important rare earth ions emitting light in the NIR
ranges. Many glass systems have been studied for NIR luminescence
at 1.5 m associated with the
4
I
13/2
–
4
I
15/2
transition of Er
3+
ions in
relation to practical applications as a solid-state lasers and optical
amplifiers operating in the standard telecommunication window.
Some of them convert the near-infrared radiation into visible
light. The previously published works suggest that the erbium-
doped lead borate glasses and transparent glass–ceramics are
promising materials for near-infrared solid-state lasers, broadband
optical amplifiers and up-conversion luminescence applications
[4–6].
The presented paper is divided into two parts. The first
part of this paper contains results for europium-doped glasses
with various PbO/B
2
O
3
ratios in chemical composition. The local
structure around Eu
3+
in lead borate glass was examined. The
structure–property relationship is evidenced by Raman, FT-IR and
luminescence spectroscopy.
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.04.022