Luminescence properties of sol-gel derived Sr2(Ce1−xSnx)O4 blue phosphors

Monophasic Sr2(Ce1−xSnx)O4 phosphors (x = 0-0.07) were prepared via the sol-gel process. A broad excitation band ascribed to the Ce4+-O2− transition was observed in the range of 200-450 nm. With doping Sn4+ ions into the host, the intensity of the low-energy peak enhanced remarkably due to a decrease in crystal field. The intensity ratio of the low-energy peak to the high-energy peak increased with the amount of Sn4+ ions doped. Moreover, the red shift of the excitation peaks was observed due to an increase in the bond length of Ce-O. Upon excitation at around 346 nm, the intensity of the blue emission peak peaking at 483 nm was enhanced with doping Sn4+ ions. The doping of tin ions was found to significantly improve the luminescence characteristics of the prepared phosphors when they were excited under UV light.