Effects of charge compensation on red emission in CaYAl3OT7：Eu3＋ phosphor

Monovalent ions Li＋, Na＋, and K＋, as charge compensators, are introduced into CaYA1307： M （M = Eu3＋, Ce~＋） in this letter. Their crystal phases and photoluminescence properties of different alkali metal ions doped in CaYA1307 are investigated. In addition, the influence of charge compensation ion Li＋ which has a more obvious role in improving luminescence intensity on CaYA1307： Eu3＋ phosphor is intentionally discussed in detail and a possible mechanism of charge compensation is given. The enhancement of red emission centered at 618 nm belonging to Eu3＋ is achieved by adding alkali metal ion Li＋ under 393-nm excitation.     

Energy transfer mechanism in Er3＋ doped fluoride glass sensitized by Tm3＋ or no3＋ for 2.7-μm emission

Enhanced 2.7 μm emission is obtained in Er3＋/Tma＋ and Era＋/Ho3＋ codoped ZBYA glasses. Absorp- tion and emission spectra are tested to characterize the 2.7 μm emission properties of Era＋/Tm3＋ and Era＋/Ho3＋ doped ZBYA glasses and a reasonable energy transfer mechanism of 2.7 μm emission between Er3＋ and Tm3＋Ho3＋） ion is proposed. Codoping of Tm3＋ or Ho3＋ significantly reduces the lifetime of the Era＋： 4I13/2 level due to the energy transfer of Er3＋：4I13/2 →Tm3＋：3F4 or Er3＋：4I13/2 →Ho3＋： 5I7. Thus, the 2.7μm emission is strengthened and the 1,5μm emission is decreased accordingly especially in the Era＋/Tma＋ sample. The upconversion effects between the Er3＋/Tm3＋ and Er3＋/Ho3＋ doped ZBYA glasses are different attribute to the different energy transfer efficiencies. Both of the two codoped samples possess nearly equal large emission cross section （16.6 × 10 -21 cm-2） around 2.7 μm. The results indicate that this Er3＋/Tm3＋ or Er3＋/Ho3＋ doped ZBYA glass has potential applications in 2.7 μm laser.     

Empowering perovskite PbTiO3 nanoparticles with enhanced up-conversion luminescence and thermal sensitivity by introducing Er3+ dopant

Up-convertion(UC)perovskite Er³⁺-doped Pb TiO3(Er-PTO)nanoparticles with green and red emissions were synthesized via the hydrothermal method.The UC properties were manipulated by adjusting the concentration of Er³⁺ ions dopant.The green emission intensity was decreased as the doping concentration increased from 1% to 4%(mole fraction),whereas the red emission intensity was increased.The influences of Er³⁺ ions on the temperature-sensing performance were further investigated.The results demonstrated that Er-PTO nanoparticles with doping 1% Er³⁺ ions possessed a sensitivity of3.1×10^-3 K^-1 at 475 K,presenting a high potential in optical heating devices.