Luminescence and defect centres in Tb(3+) doped LaMgAl(11)O(19) phosphors


Autoria(s): SINGH, Vijay; Watanabe, Shigueo; RAO, T. K. Gundu; KWAK, Ho-Young
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/10/2012

20/10/2012

2010

Resumo

Terbium (Tb) doped LaMgAl(11)O(19) phosphors have been prepared by the combustion of corresponding metal nitrates (oxidizer) and urea (fuel) at furnace temperature as low as 500 C Combustion synthesized powder phosphor was characterized by X-ray diffraction and field emission scanning electron microscopy techniques LaMgAl(11)O(19) doped with trivalent terbium ions emit weakly in blue and orange light region and strongly in green light region when excited by the ultraviolet light of 261 nm Electron Spin Resonance (ESR) studies were carried out to study the defect centres Induced in the phosphor by gamma irradiation and also to identify the defect centres responsible for the thermally stimulated luminescence (TSL) process Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of at least two defect centres One of the centres (centre I) with principal g-values g(parallel to) = 2 0417 and g(perpendicular to) = 2 0041 is identified as O(2)(-) ion while centre II with an axially symmetric g-tensor with principal values g(parallel to) = 19698 and g(perpendicular to) = 1 9653 is assigned to an F(+) centre (singly ionized oxygen vacancy) An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F centre (oxygen vacancy with two electrons) The F centre and also the F+ centre appear to correlate with the observed high temperature TSL peak in LaMgAl(11)O(19) Tb phosphor (C) 2010 Elsevier Masson SAS All rights reserved

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

FAPESP Brazil

Identificador

SOLID STATE SCIENCES, v.12, n.12, p.1981-1987, 2010

1293-2558

http://producao.usp.br/handle/BDPI/29451

10.1016/j.solidstatesciences.2010.08.012

http://dx.doi.org/10.1016/j.solidstatesciences.2010.08.012

Idioma(s)

eng

Publicador

ELSEVIER SCIENCE BV

Relação

Solid State Sciences

Direitos

restrictedAccess

Copyright ELSEVIER SCIENCE BV

Palavras-Chave #LaMgAl(11)O(19) #Combustion #Luminescence #Defect centres #Tb(3+) #ESR #ELECTRON-SPIN-RESONANCE #THERMALLY STIMULATED LUMINESCENCE #ALUMINATE SINGLE-CRYSTALS #ENERGY-TRANSFER #LANTHANUM HEXAALUMINATE #PARAMAGNETIC-RESONANCE #MAGNETIC-PROPERTIES #SATURABLE ABSORBER #OPTICAL-PROPERTIES #BARRIER COATINGS #Chemistry, Inorganic & Nuclear #Chemistry, Physical #Physics, Condensed Matter
Tipo

article

original article

publishedVersion