Tunable blue–green–yellow
emitting Sr3YNa(PO4)3F (SYNPF):Ce3+,Tb3+,Mn2+ phosphors have been prepared
via a high-temperature
solid-state reaction method. The structural and luminescent properties,
energy transfer (ET) mechanism, and thermal quenching of the samples
are investigated in detail. The ET from Ce3+ to Tb3+ and Mn2+ in SYNPF is identified as the interaction
of the electric dipole–quadrupole with ET efficiencies of 81.6%
and 69.3%, respectively. The critical distances for Ce3+/Tb3+ and Ce3+/Mn2+ are calculated
through the spectral overlap method to be 9.54 and 10.92 Å. Under
UV excitation, high-efficiency tunable blue–green–yellow
emissions from Ce3+ to Tb3+ and Mn2+ can be obtained. Moreover, white light can also be achieved by adjusting
the stoichiometry of Ce3+ and Mn2+ properly
in the SYNPF phosphor. In addition, the temperature-dependent luminescence
spectra exhibit good thermal quenching behaviors for the as-prepared
phosphors. The above results suggest that SYNPF:Ce3+,Tb3+,Mn2+ phosphors can act as color-tunable emission
phosphors for potential applications in WLEDs.
A series of color-tunable Sr 3 YNa(PO 4 ) 3 F:Tb 3+ phosphors with a fluorapatite structure were synthesized by a traditional high-temperature solid state reaction. The emitting color tuning from blue to green can be observed by gradually increasing Tb 3+ concentrations, which is attributed to the enhanced crossrelaxation (CR) between Tb 3+ ions, as described by ( 5 D 3 , 7 F 6 )-( 5 D 4 , 7 F 0 ). The CR process is analyzed based on the Dexter and Inokuti-Hirayama model, which is assigned to the electric dipole-dipole interaction. The energy transfer critical distance between Tb 3+ ions is evaluated to be 18.1Å. In addition, the thermal quenching mechanism of Sr 3 YNa(PO 4 ) 3 F:Tb 3+ is also investigated. At the general working temperature of an LED (423 K), the luminescence intensity still maintains 81% and 92% with the Tb 3+ concentration of 10 and 30 mol%, respectively, indicating an excellent thermal quenching performance of Tb 3+ . Due to the good optical and thermal properties, the Sr 3 YNa(PO 4 ) 3 F:Tb 3+ phosphor can be used as a promising green emitting phosphor candidate in the field of white light applications.
Reducing interface recombination losses is one of the major challenges in developing Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells. Here, we propose a CZTSSe solar cell with an atomic layer deposited Al 2 O 3 thin film for surface passivation. The influence of passivation layer thickness on the power conversion efficiency
High efficient single−component full−color emitting Ca6Y2Na2(PO4)6F2 (CYNPF): Eu2+, Tb3+, Mn2+ phosphors have been synthesized by high−temperature solid−state reaction. Coupled with the Eu2+, Tb3+, and Mn2+ emission bands centered at 455...
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