NATIONAL
INSTITUTE for LASER, PLASMA and RADIATION PHYSICS LABORATORY of SOLID-STATE QUANTUM ELECTRONICS |
|
II. Study of the
influence of
preparation conditions on the emission properties of phosphors powders
with
langasit structure.
III. Study of the
effects of the substitution of Ga3+
ions by Al3+ and In3+ in
various compounds from the
langasite family on their luminescence properties.
REZULTATE
2009:
•
Au fost sintetizate pulberi de
langasit (La3Ga5SiO14),
langatat (La3Ga5.5Ta0.5O14)
si langanit (La3Ga5.5Nb0.5O14)
dopate cu Eu3+ si au fost tratate termic in aer
la temperaturi pana
la 1350ŗC.
-
S. Georgescu, A.M.
Voiculescu, O. Toma, C. Tiseanu, L. Gheorghe, A. Achim, C. Matei,
”Eu-doped
langasite, langatate, and langanite - possible new red phosphors,”
Abstract Book, ISSN 1842-3574,
page 28.
-
A.M. Voiculescu, S.
Georgescu, L. Gheorghe, A. Achim, O. Toma, C. Matei, M. Osiac ”Growth
and
characterization of the partially disordered La3Ga5.5-xAlxTa0.5O14
single crystals doped with
Eu3+,”
Abstract
Book, ISSN 1842-3574, page 23.
•
La Conferinta Internationala Micro-
to Nano-Photonics II -
ROMOPTO 2009, 31 August - 3 Septembrie 2009, Sibiu, Romania, a fost
prezentata lucrarea:
-
S. Georgescu, A.M.
Voiculescu, O. Toma, L. Gheorghe, A. Achim, C. Matei, I. Enculescu, E.
Matei,
M. Osiac, ”Optical and morphologic properties of YVO4:Eu phosphor, ”
presentation III.P.1.
• A fost publicata lucrarea:
1.
S. Georgescu, A. M. Voiculescu, O. Toma, C.
Tiseanu,
L. Gheorghe, A. Achim, C. Matei, "Eu-doped
langasite, langatate and langanite - possible new red
phosphors,”
Optoelectronics
and Advanced Materials - Rapid Communication 3 (12), 1379-1382
(2009).
2. S.
Georgescu, A.M. Voiculescu, C. Matei. O.
Toma, L. Gheorghe, A. Achim, “Reflectance measurements on
europium-doped langasite,
langanite and langatate powders,”
Romanian
Reports in Physics 62 (1), 128-133, (2010).
2010:
•
Au fost sintetizate pulberi de
langasit langanit (La3Ga5.5Nb0.5O14)
in care Ga3+ a fost substituit partial cu Al3+
sau In3+.
•
Pulberile obtinute au fost tratate termic la temperaturi
cuprinse intre 700ŗC si 1100ŗC.
•
Pulberile au fost caracterizate prin XRD, FTIR si
spectroscopie optica (luminescenta, reflactanta difuza, cinetica
nivelelor
metastabile).
•
Spectrele de reflectanta difuza arata ca in urma
tratamentelor termice pulberile capata o culoare rosie, culoare care se
intensifica cu temperatura de tratament. Aceasta colorare ecraneaza
radiatia de
pompaj (~ 400 nm), ducand la scaderea eficientei emisiei.
•
In urma tratamentelor termice la temperaturi ridicate, o
parte din faza de langanit se transforma in perovskit (LaGaO3);
substituirea a 10-at.% din Ga3+ cu Al3+
franeaza
aparitia fazei de perovskit.
1.
S.
Georgescu, A.M. Voiculescu, O. Toma, S. Nastase, C. Matei, M. Osiac,
„Luminescence of Eu-doped langanite nanopowders synthesized by a citrate
sol–gel
method,”
Journal of Alloys and Compounds 507 (2), 470-474 (2010).
2.S. Georgescu, A.
M. Voiculescu, O. Toma, L. Gheorghe, A. Achim, C. Matei, S. Hau,
“Luminescence efficiency
of europium-doped LGS, LGT and LGN crystals”, Optoelectronics and
Advanced Materials - Rapid
Communication 4 (12), (acceptata spre publicare).
•
Articole
trimise la publicare īn
cursul anului 2011:
1. S.
Georgescu, A. M. Voiculescu,
S. Nastase, O. Toma, C. Matei, and R. Bīrjega, “Effect of aluminum
substitution on
the phase stability and luminescence properties of Eu-Doped langanite
nano-powders synthesized by a citrate sol-gel method”, trimisă la
Romanian
Reports in Physics.
2. S.
Georgescu, O. Toma, A. M. Voiculescu, C. Matei, R. Bīrjega, and L.
Petrescu, “Infrared-excited bright green
and red
luminescence in La3Ga5.5Ta0.5O14
doped with erbium and ytterbium”,
trimisă la Physica B.
•
Mobilităţi
īn 2011:
A. Participarea
a două
persoane la "International student workshop on laser applications”, May 31 - June 4, 2011, Bran-Romania:
A.1.
Voiculescu Ana-Maria, Georgescu
Serban, Matei Cristina, Toma Octavian, Nastase Silviu, Bīrjega
Ruxandra,
“Upconversion luminescence of langanite powders doped with erbium and
ytterbium”.
A.2. Matei Cristina, Georgescu
Serban, Voiculescu Ana-Maria, Toma Octavian, Nastase Silviu,
“Luminescence
properties of Eu-doped La3(Ga1-xAlx)5.5Nb0.5O14
nano-powders synthesized by a citrate
sol-gel method”
B.1.
Ana-Maria Voiculescu, Serban
Georgescu, Ruxandra Bīrjega, Octavian Toma, Cristina Matei, Livia
Petrescu,
Ionuţ Enculescu, Elena Matei, “Infrared-excited
bright green and red luminescence
in La3Ga5.5Ta0.5O14
doped with erbium and ytterbium”.
C. Participarea
a două persoane la: “Physics Conference TIM-11”,
November 24-27, 2011,
C1. A.
M. Voiculescu, S. Georgescu,
O. Toma, C. Matei, R. Bīrjega, L. Petrescu, “Luminescence properties of
La3Ga5.5Ta0.5O14
doped with erbium and ytterbium”.
C2. Matei
E. C., Georgescu S., Voiculescu A, M., Toma O., Năstase S.,
“Luminescence
properties of Eu-doped La3(Ga1-xAlx)5.5Nb0.5O14
nano-powders synthesized by a citrate sol-gel method”.
Laboratory
of Solid-State Quantum Electronics
|