Effects of NaCl flux on microstructure and luminescent characteristics of KSrPO4:Eu2+ phosphors

• Published in: Optical materials 2012-07, Vol.34 (9), p.1598-1602
• Main Authors: Su, Yan-Kuin, Peng, Yu-Ming, Yang, Ru-Yuan, Chen, Jian-Liang
• Format: Article
• Language: English
• Subjects: Crystals; Energy transfer; Flux; KSrPO4; Luminescence; Microstructure; NaCl; Particle size; Phosphors
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2012.03.019

► The fluxes affected the formation of the phosphors in the high temperature sintering. ► Flux method has potential advantages and the ability to control the particle size of products. ► The particle size of the KSr0.99PO4:0.01Eu2+ phosphors can be enhanced with addition of NaCl flux. ► The maximum photoluminescence intensity of KSr0.99PO4:0.01Eu2+ phosphors was 6wt.%. KSr0.99PO4:0.01Eu2+ phosphors were synthesized in succession by adding different NaCl flux concentrations (0, 2, 4 and 6wt.%). The sintering condition was set at 1300°C for 3h under 97% N2/3% H2 atmosphere. The effect of NaCl flux on the microstructural and luminescent characteristics of KSr0.99PO4:0.01Eu2+ phosphors were investigated and discussed. The XRD results showed that the phase purity of KSr0.99PO4:0.01Eu2+ phosphors could be improved after adding NaCl flux. The EDS data showed that the peaks of NaCl flux were not detected. The SEM images showed that the particle size became bigger when more NaCl flux was added. It was also observed that many little fragments on the surface appeared as the NaCl flux increased to 4wt.% and 6wt.%. Additionally, all of the KSr0.99PO4:0.01Eu2+ phosphors emitted blue luminescence under UV excitation. The use of the NaCl flux in KSrPO4 may cause the change the crystal field of KSrPO4 but not the change in the energy transfer mechanism among Eu2+ ions.