Search

Pure and Eu2+‐activated fluoroborate BaGaBO3F2 was prepared using high‐temperature solid‐state reaction. BaGaBO3F2 is a wide band semiconductor with the indirect transition characteristic. The excitation and luminescence spectra of the phosphor were measured, and it was found that Eu2+‐activated BaGaBO3F2 exhibits a bright blue color under ultraviolet (UV) light. The narrow emission band peaked at 425 nm is attributed to the transitions of 4f65d→4f7(8S7/2), and the Stokes shift estimated for this phosphor sample is 3140 cm−1. The lifetime of the luminescence is also reported. The absolute quantum efficiency (QE) of the phosphor was evaluated, and it was found that the absolute QE decreases with increasing Eu2+ concentration. The phosphor shows an excellent quantum efficiency of 72.5% and a high thermal activation energy of 0.342 eV. The study concludes that Eu2+‐doped BaGaBO3F2 phosphor has promising luminescence application abilities and can be used as a blue‐emitting phosphor in a variety of applications. [ABSTRACT FROM AUTHOR]

Pure and Eu2+‐activated fluoroborate BaGaBO3F2 was prepared using high‐temperature solid‐state reaction. BaGaBO3F2 is a wide band semiconductor with the indirect transition characteristic. The excitation and luminescence spectra of the phosphor were measured, and it was found that Eu2+‐activated BaGaBO3F2 exhibits a bright blue color under ultraviolet (UV) light. The narrow emission band peaked at 425 nm is attributed to the transitions of 4f65d→4f7(8S7/2), and the Stokes shift estimated for this phosphor sample is 3140 cm−1. The lifetime of the luminescence is also reported. The absolute quantum efficiency (QE) of the phosphor was evaluated, and it was found that the absolute QE decreases with increasing Eu2+ concentration. The phosphor shows an excellent quantum efficiency of 72.5% and a high thermal activation energy of 0.342 eV. The study concludes that Eu2+‐doped BaGaBO3F2 phosphor has promising luminescence application abilities and can be used as a blue‐emitting phosphor in a variety of applications. [ABSTRACT FROM AUTHOR]

Ce3+/Tb3+ co-doped BaGaBO 3 F 2 is a new rare-earth activated luminescent material with efficient green luminescence. The phosphor was synthesized via the conventional solid-state reaction and characterized by X-ray powder diffraction, photoluminescence, and decay lifetimes. The Ce3+/Tb3+ co-doped phosphor exhibits an efficient excitation between 280 and 420 nm, making it suitable for commercial near-UV chips. The 4f–5d transitions of Ce3+ sensitizer allow the phosphor to be excited by the near-UV light, resulting in green and blue luminescence from Tb3+ and Ce3+, respectively. By controlling Ce3+/Tb3+ doping, the luminescence color can be tuned from blue to green. The effective transfer of excitation energy from Ce3+ to Tb3+ of BaGaBO 3 F 2 was confirmed by the spectral characteristics and decay lifetimes of samples with different doping concentrations. The dipole-quadrupole mechanism is responsible for the efficient energy transfer from Ce3+ to Tb3+, with a critical distance of 11.69 Å. These results demonstrate that Ce3+/Tb3+ co-doped BaGaBO 3 F 2 is an efficient near-ultraviolet (NUV) excitation phosphor with tunable luminescence from blue to green. This material has the potential to be used as a down-conversion phosphor for NUV light-emitting diodes. • Ce3+/Tb3+ co-doped BaGaBO 3 F 2 is a new rare-earth activated material. • Ce3+ acts as a sensitizer to efficiently transfer excitation to activators. • Luminescence color can be tuned from blue to green in BaGaBO 3 F 2 :Ce3+/Tb3+. • It is potential as a down-conversion phosphor for NUV LEDs. [ABSTRACT FROM AUTHOR]

Abstract: Ce-doped La2Si2O7 (LaPS:Ce) polycrystalline powders were successfully prepared through a sol–gel technique at lower temperature. The X-ray diffraction measurements confirmed that the Ce-doped powders were a kind of monophase solid solution. Photoluminescence, radioluminescence, and decay time characteristics of the prepared powders have been systematically investigated and discussed. It was noticed that the LaPS:Ce material shows an excellent light yield in comparison with commercial Y3Al5O12:Ce (YAG:Ce) powders under X-ray excitation. The LaPS:Ce sample demonstrated a high temperature stability of luminescence yield up to 250°C and a short decay time. Therefore, the LaPS:Ce powder is proposed to be a novel and promising scintillator material. [Copyright &y& Elsevier]