Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 9, pp. 1459−1462.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © A.P. Savikin, A.V. Budruev, A.N. Shushunov, I.A. Grishin, E.L. Tikhonova, 2013, published in Zhurnal Prikladnoi Khimii, 2013,
Vol. 86, No. 9, pp. 1493−1496.
Visualization of IR Radiation by Fluoride Ceramics
A. P. Savikin, A. V. Budruev, A. N. Shushunov, I. A. Grishin, and E. L. Tikhonova
Lobachevskii State University, Nizhni Novgorod, Russia
Received July 19, 2013
Abstract—Ceramic luminophors based on YF
(Er, Yb) and LiYF
(Er, Yb) solid solutions were obtained in the
form of tablets by the solid-phase synthesis in the temperature range 800–1000°С. The synthesized luminophors
can be used in the form of thin-ﬁ lm lacquer coats phosphorescing under the action of IR radiation, for recording
hidden information, for defense of goods and securities, and for adjustment of IR lasers.
Depending on a ratio of exciting and emitted light
frequencies, two types of luminescence are observed:
Stokes and anti-Stokes or up-conversion. If the frequency
increases, the radiation transition is observed in the anti-
The probability of one or another electronic transition
is deﬁ ned by the energy of phonons of a matrix, in which
an active element, for example a rare-earth ion, is inserted.
An electron is able to transit from an excited state down-
wards radiationless or by losing energy due to light radia-
tion. In the case of the radiationless electron transition
from an excited level on a lower level an electron–phonon
interaction occurs accompanied by the energy transfer to
a matrix by generation of optical phonons.
The probability of such energy transfer depends on
the energy gap between electronic terms and phonons
characteristic of this matrix. As the energy of phonons
decreases, this probability also decreases , and the
probability (and the effectiveness) of the transition with
a frequency increase, i.e. of visualization of the exciting
radiation increases if, for example, it is an IR radiation.
The most impressive data on the role of phonon energy
were obtained in the work , in which thulium (Tm
up-conversion in a silica–alumina glass was investigated.
The energy of phonons in this glass is approximately
equal to 1200 cm
that favors transitions in the Stokes
region, whereas the thulium up-conversion is rather weak.
To intensify thulium up-conversion, 28 mol % of PbF
and 22 mol % of CdF
were included in the glass com-
position. Upon heating the glass these ﬂ uorides drop out
(are separated) as the crystalline nanophase Pb
enriched in Nd
, and Tm
ions. The effect of
thulium up-conversion intensiﬁ cation is connected with
the fact that the phonon energy of the ﬂ uoride crystalline
phases is much less than 500 cm
, which hampers the ra-
diationless transition from the thulium upper excited level
and favors the transition to the ground state
the wave length λ = 480 nm (dark blue-light emission).
The thulium up-conversion effect in  is reached
owing to the formation of the nanocrystal low-phonon
(d = 17.8 nm) and to the usage of two
donor elements: neodymium and ytterbium. Ytterbium
has proved itself worth as an effective donor in a pair
with erbium. In this case, depending on a matrix, pre-
dominating transitions for erbium are up-conversion
(ﬂ uoride glass) [3, 4] or a transition with λ = 1.55 μm,
which made this element demanded in ﬁ ber ampliﬁ ers
for optical communication.
In recent years anti-Stokes luminophors based on
Er–Yb double doped materials ﬁ nd application in color
displays, optical memory devices, as a visible light source,
and for cancer diagnostic and therapy .
In the 1990s we studied energy transfer processes in
a ﬂ uorozirconate glass doped by binary and ternary Er
mixtures of ions. The
introduction of the third rare-earth element holmium has
led to a more efﬁ cient conversion of pumping energy
to a green radiation (0.52–0.54 μm). Holmium spectral