Synthesis And Photoluminescence Properties Of Ba₃Al₂O₆:Eu And Its Oxynitride Phosphors

The red phosphors are successfully synthesized by high temperature solid state reaction and they can be efficiently excited by NUV-LED chips.On basis of the red phosphors,adding Si4+ and N3-,the green oxynitride phosphors can be produced in the reducing atmosphere and it can be efficiently excited by NUV-LED chips and blue-LED chips.The main work and results are as follows:?1?The study of the effect of sintering temperature on the photoluminescence property of Ba₃Al₂O₆:0.06Eu³⁺ phosphorThe phosphor synthesized at different sintering temperature is Ba₃Al₂O₆ phase,with little Ba CO₃ unresolved at low temperature.The doping of Eu³⁺ doesn't change its crystal structure.The morphology of phosphor has great relationship with the sintering temperature.In the emission pattern of phosphor,the red-orange emission peak can be seen,corresponding to5D0?7F1 and 5D0?7F2 transition of Eu³⁺ ions.The luminous intensity increases with the increase of sintering temperature,and 1450°C is the best sintering temperature.?2?The study of the effect of Eu³⁺ concentration on the photoluminescence property of Ba₃Al₂O₆:x Eu³⁺?x=0.02,0.04,×××,0.16?phosphorThe Eu³⁺ concentration has a great influence on the pure-phase sample synthesis.When x>12mol%,large amount of impurity phase appears.When x<12mol%,the intensity of the excitation peak strengthens with the increase of the Eu³⁺ concentration,together with the red shift.At the same time,the intensity of the emission peak increases when the Eu³⁺concentration increases and then the concentration quenching happens.When x<12mol%,the symmetry around the Eu³⁺ becomes better with Eu³⁺ concentration increase,on the contrary,the symmetry decreases.Thus,the best Eu³⁺ concentration is 12mol%.?3?The study of the effect of charge compensators on the photoluminescence property of Ba₃Al₂O₆:0.06Eu³⁺,0.06Z?Z=Li⁺?Na⁺?K⁺?phosphorThe addition of charge compensators doesn't change the phosphor's crystal structure.The addition of all these three ions strengthens its luminous intensity,and Li⁺ is the best,then K⁺ and Na⁺ the worst.?4?The study of the effect of reducing atmosphere on the photoluminescence property of Ba₃Al₂O₆:0.06Eu²⁺ phosphorThe phosphor's main crystalline phase sintered at the reducing atmosphere is Ba₃Al₂O₆,but still with a little of Ba CO₃ phase.The luminous intensity of the phosphor reduced at the NH₃ atmosphere is twice than that at the N₂/H₂.?5?The study of the effect of N concentration on the photoluminescence property of(Ba_0.94Eu_0.06)₃A_l2-x Si_x O_6-x N_x?x=0,0.2,×××,2?phosphorWith the increase of N,the structure of the phosphor transforms from Ba₃Al₂O₆ phase to the combination of Ba2 Si O₄ phase and Ba Al2O₄ phase,and the content of Ba Al2O₄ phase is decreasing.In the phosphor's emission spectrum,there is a green-light broad peak corresponding to d?f transition of Eu²⁺ ions.When x<1,the luminous intensity of the sample doesn't change much with the x increase.When x>1,it strengthens a lot.When x=1.6,the luminous intensity is the best and the excitation peak is the widest.The pattern of XPS shows that Si4+ and Al³⁺ have no interaction reciprocity in the reaction process,but N3-gradually replaces O2-and enters the crystal structure.?6?The study of the effect of Eu²⁺ concentration on the photoluminescence property of(Ba_1-y Eu_y)₃Al_0.4Si_1.6O_4.4N_1.6?y=0.02,0.04,×××,0.12?phosphorThe synthesized phosphor is Ba₂ Si O₄ phase.N₃-replaces O₂^-and enters matrix crystal structure,and the doping of Eu²⁺ doesn't change the phosphor's structure.It can be seen from the emission spectrum that the best concentration of Eu²⁺ is 4mol%,and the emission peak occurs red shift with the increase of the Eu²⁺ concentration.The CIE coordinates changes from blue-green to yellow-green.Therefore,Ba₃Al₂O₆:Eu³⁺,Li⁺ red phosphor is potential candidate for UV-excited white-LED.(Ba_0.96Eu_0.04)₃Al_0.4Si_1.6O_4.4N_1.6 green oxynitride phosphor is expected to be a multipurpose phosphor that can be motivated by UV,NUV or blue light for the white-LED.