TY - JOUR
T1 - Exciton interaction with Ce3+ and Ce4+ ions in (LuGd)3(Ga,Al)5O12 ceramics
AU - Khanin, Vasilii
AU - Venevtsev, Ivan
AU - Chernenko, Kirill
AU - Pankratov, Vladimir
AU - Klementiev, Konstantin
AU - van Swieten, Thomas
AU - van Bunningen, Arnoldus J.
AU - Vrubel, Ivan
AU - Shendrik, Roman
AU - Ronda, Cees
AU - Rodnyi, Piotr
AU - Meijerink, Andries
PY - 2021/9
Y1 - 2021/9
N2 - Scintillators based on Ce-doped garnets are regularly co-doped with Mg2+ or Ca2+ to form Ce ions in 4+ state and reduce undesired afterglow. However overly high Ce4+ concentration leads to poor light yield performance. In order to understand the reason for variation in luminescence efficiency of Ce3+- and Ce4+-doped garnets we investigate the differences in energy conversion processes in complex LuGd2Ga3Al2O12:Ce3+/Ce4+ ceramics by means of VUV synchrotron irradiation. At first we have established via transmission spectroscopy and X-ray absorption spectroscopy that LuGd2Ga3Al2O12:Ce, Mg sample contains cerium in the 4+ state only. Then we show with VUV spectroscopy efficient interaction of excitons with Gd3+ and Ce3+, and lack of exciton absorption edge in LuGd2Ga3Al2O12:Ce4+ excitation spectrum. Instead, Ce4+ exhibits charge-transfer absorption band in the range of exciton emission. We suggest that when Ce4+ concentration becomes too high, the exciton → Gd3+ → Ce3+ energy transfer path is hindered. It leads to high intensity of Gd3+ luminescence in Lu1Gd2Ga3Al2O12:Ce, Mg ceramics, but lowered Ce3+ X-ray excited luminescence. Fine balance between 3+ and 4+ Ce concentrations is necessary to achieve the best performance of garnet scintillators.
AB - Scintillators based on Ce-doped garnets are regularly co-doped with Mg2+ or Ca2+ to form Ce ions in 4+ state and reduce undesired afterglow. However overly high Ce4+ concentration leads to poor light yield performance. In order to understand the reason for variation in luminescence efficiency of Ce3+- and Ce4+-doped garnets we investigate the differences in energy conversion processes in complex LuGd2Ga3Al2O12:Ce3+/Ce4+ ceramics by means of VUV synchrotron irradiation. At first we have established via transmission spectroscopy and X-ray absorption spectroscopy that LuGd2Ga3Al2O12:Ce, Mg sample contains cerium in the 4+ state only. Then we show with VUV spectroscopy efficient interaction of excitons with Gd3+ and Ce3+, and lack of exciton absorption edge in LuGd2Ga3Al2O12:Ce4+ excitation spectrum. Instead, Ce4+ exhibits charge-transfer absorption band in the range of exciton emission. We suggest that when Ce4+ concentration becomes too high, the exciton → Gd3+ → Ce3+ energy transfer path is hindered. It leads to high intensity of Gd3+ luminescence in Lu1Gd2Ga3Al2O12:Ce, Mg ceramics, but lowered Ce3+ X-ray excited luminescence. Fine balance between 3+ and 4+ Ce concentrations is necessary to achieve the best performance of garnet scintillators.
KW - Ce4+
KW - Energy transfer
KW - Excitons
KW - Garnet scintillators
KW - Synchrotron
KW - XANES
UR - https://www.mendeley.com/catalogue/02f3aab0-be2a-382c-ab0f-a08592a0268d/
U2 - 10.1016/j.jlumin.2021.118150
DO - 10.1016/j.jlumin.2021.118150
M3 - Article
SN - 0022-2313
VL - 237
SP - 1
EP - 6
JO - Journal of Luminescence
JF - Journal of Luminescence
M1 - 118150
ER -