Chapter 6 Luminescence of Pb- and Bi-Related Centers in Aluminum Garnet, Perovskite, and Orthosilicate Single-Crystalline Films

Thermoluminescent Properties of Cerium-Doped Lu2SO5 and Y2SiO5 Single Crystalline Films Scintillators Grown from PbO-B2O3 and Bi2O3 Fluxes

“…Nominally undoped and cerium-doped LSO and YSO SCFs were prepared onto undoped YSO substrates ( Table 1). The SCFs were grown by the LPE method from a super-cooled melt-solution based on two different fluxes: PbO-B 2 O 3 (samples 1, 2 and 5, 6) and Bi 2 O 3 (samples 1, 2 and 5, 6) ( Table 1, see also [8,15] for details). The samples were doped with cerium ions using CeO 2 activator with concentration in the 10-20% range.…”

“…The emission bands peaked at 374/365 nm correspond to the 3 P1→ 1 S0 transitions of Pb 2+ ions in Y1/Lu1 sites of YSO and LSO hosts with seven oxygen ligands [7,16] (further noted as Pb1 centers, respectively). The nature of the 434/446 nm emission bands (Pb2 centers) is still not clear, and can been interpreted as: (i) the emission of the excitons localized around Pb 2+ based centers [6][7][8]; (ii) the luminescence of Pb 2+ ions inY1/Lu1 sites of the X2 structure with seven oxygen ligands or in Y2/Lu2 sites of the X1 structure with six oxygen ligands [15,22]. The CL spectra of nominally undoped YSO and LSO SCFs grown from PbO based flux are shown in Figure 2a,b, curves 2, respectively.…”

“…(ii) the luminescence of Pb 2+ ions in Y1/Lu1 sites of the X2 structure with seven oxygen ligands or in Y2/Lu2 sites of the X1 structure with six oxygen ligands [15,22].…”

“…On the other hand, in LSO:Ce and YSO:Ce SCFs grown by the LPE method from Bi 2 O 3 flux, mainly the Ce 3+ valence state is realized in these SCFs in the case of the incorporation of isovalent Bi 3+ ions as flux agent [8,14,15]. Therefore, in these SCFs we can mainly expect the formation of Bi 3+and Ce 3+ -based centers [8,15].…”

“…On the one hand, the large lead contamination of LSO:Ce and YSO:Ce SCFs in the 0.02-0.19 at.% range (see Table 1) can lead also to the creation of Ce 4+ -and Pb 2+ -based centers with local charge and volume compensation, which can also be involved in the TL processes in these SCFs as emission centers [8]. On the other hand, in LSO:Ce and YSO:Ce SCFs grown by the LPE method from Bi 2 O 3 flux, mainly the Ce 3+ valence state is realized in these SCFs in the case of the incorporation of isovalent Bi 3+ ions as flux agent [8,14,15]. Therefore, in these SCFs we can mainly expect the formation of Bi 3+and Ce 3+ -based centers [8,15].…”