A new rare-earth oxyborate Ba₃BiPbEuO(BO₃)₄and the luminescence properties of the Ba₃BiPbY_1−xEu_xO(BO₃)₄phosphors

Abstract

A new borate Ba3BiPbEuO(BO3)4 was synthesized and characterized and the luminescence properties of Ba3BiPbY1−xEuxO(BO3)4 (0 ≤ x ≤ 1) were investigated.

Two new rare-earth oxyborates Ba4BiTbO(BO3)4 and Ba1.54Sr2.46BiTbO(BO3)4 and luminescence properties of the Ba4BiTb1−xEuxO(BO3)4 phosphors

“…These are common values as found in other known borates. 33,38 The calculated total bond valences for Ba1, Ba2, Tb, B1, and B2 are 2.049, 2.052, 3.282, 2.991, and 2.937, respectively, consistent with their expected oxidation states. 39 Although the title compounds are isostructural with our previously reported Pb 2+ -analog, Ba 3 BiPbEuO(BO 3 ) 4 , their crystal structures show a certain difference.…”

“…39 Although the title compounds are isostructural with our previously reported Pb 2+ -analog, Ba 3 BiPbEuO(BO 3 ) 4 , their crystal structures show a certain difference. 33 For example, in Ba 3 BiPbEuO(BO 3 ) 4 , both Pb 2+ and Bi 3+ cations are located at the same 4e site with identical positional and thermal parameters, while in Ba 4 BiTbO(BO 3 ) 4 [Ba 1.54 Sr 2.46 BiTbO(BO 3 ) 4 ], this site is split into two very close positions, occupied by Ba 2+ and Bi 3+ (Sr 2+ and Bi 3+ ), respectively. This is understandable because both Pb 2+ and Bi 3+ have a 6s 2 electron conguration and, of course, a similar coordination environment, while the ionic radii and coordination geometries around Ba 2+ and Bi 3+ as well as Sr 2+ and Bi 3+ are very different.…”

A new melilite-type rare-earth borate CdTbGaB2O7 and multicolor tunable emission in the CdTb1−xSmxGaB2O7 (0 ≤ x ≤ 0.2) phosphors

“…Furthermore, the emission intensities are integrated over the spectral range of 450–750 nm, and are normalized as compared to the case of 303 K. The results in the inset of Fig. 9(a) show that the relative emission intensity of CdTb 0.995 Sm 0.005 GaB 2 O 7 at 423 K (the temperature at which LEDs typically operate) remains about 94% of that at 303 K. Compared with some previously reported phosphors, such as Ba 3 BiPbEuO(BO 3 ) 4 (37%), Ba 2 Lu 4.48 Eu 0.5 La 0.02 B 5 O 17 (38.2%) and LaMgAl 11 O 19 : 0.05Sm 3+ , 0.2Eu 3+ (<60%), 59,67,68 the thermal stability of CdTb 0.995 Sm 0.005 GaB 2 O 7 seems to be better. For further understanding the influence of temperature on luminescence, the activation energy of thermal quenching (Δ E ) was measured on the basis of the modified Arrhenius equation 69 :where I and I 0 are related to the PL intensity at a given temperature T and initial temperature, respectively, A is a constant for the host, and k stands for the Boltzmann coefficient (8.62 × 10 −5 eV K −1 ).…”

“…58 The fact that indirect and direct excitation leads to different quenching concentrations has already been reported in some other phosphors, such as Ba 3 BiPbY 1−x Eu x O(BO 3 ) 4 , CeO 2 : Eu 3+ and SnO 2 : Eu 3+ . [59][60][61] Fig. 4 The PLE and PL spectra of…”

Rational design of COF–MOF composites for ratiometric fluorescence detection of phosphate

“…17,18 For example, Eu 3+ ions, as part of the rare-earth family, have been widely investigated as redemitting activators due to their 5 D 0 -7 F J ( J = 0-4) leap from UV excitation. [19][20][21] Nowadays most lanthanide organic frameworkbased sensing methods of phosphate are achieved on the basis of intramolecular energy transfer by reacting with lanthanide ions or organic ligands. 22,23 However, the abovementioned lanthanide organic frameworks are single-emitting, and the sensing signal originating from fluorescent MOFs may easily be affected by probe concentration emission and excitation intensity.…”