Effect of the replacement of Al–O by Si–N on the properties of Sr 6 Si 25.6 Al 6.4 N 41.6 O 4.4 :Eu 2+ phosphors for white light-emitting diodes

• Published in: RSC advances 2015, Vol.5 (16), p.12323-12328
• Main Authors: Ma, Qian, Zhao, Chunlei, Xu, Huibing, Liu, Ronghui, Ye, Hongqi, Hu, Yunsheng, Liu, Yuanhong, Chen, Guantong
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C4RA14628J

Oxynitride phosphors Sr 6 Si 25.6−x Al 6.4+x N 41.6−x O 4.4+x :Eu 2+ are synthesized by gas pressure sintering of powder mixture of SrCO 3 , AlN, Si 3 N 4 and Eu 2 O 3 at 1800 °C and 0.5 MPa of N 2 for 10 h, and their photoluminescence properties are investigated. Sr 6 Si 25.6−x Al 6.4+x N 41.6−x O 4.4+x :Eu 2+ can be efficiently excited over a broad spectral range between 300 and 500 nm, and exhibit an intense green emission centered at about 515 nm with a full width at half maximum of 65 nm due to the 4f 6 5d 1 –4f 7 transition of Eu 2+ ions. The influence of the replacement of Si–N by Al–O on luminescence properties and crystal structure is reported in a series of Sr 6 Si 25.6−x Al 6.4+x N 41.6−x O 4.4+x :Eu 2+ phosphors. Different Sr sites are found in the crystal structure. The thermal quenching properties of the green phosphors are better than that of typical orthosilicate Ba 2 SiO 4 :Eu 2+ phosphor. Their interesting photoluminescence properties indicate that the Sr 6 Si 25.6 Al 6.4 N 41.6 O 4.4 phosphor is a promising green emitting candidate for white LEDs applications.