Effects of the pH Level on the Phosphor Characteristics of Zn2SiO4:Mn2+ Coated with SiO2 Nanoparticles

We report a green phosphor Zn 2 SiO 4 :Mn 2+ with a surface modified by coating SiO 2 nanoparticles. The phosphor was coated with SiO 2 nano-particles using a modified sol–gel method. The pH levels of phosphor solution were changed to investigate its effect on the phosphor characteristics. The SiO 2 nano-particles are coated uniformly on the surface of phosphors at pH 3.9. The surface coating of SiO 2 nano-particles on the phosphor leads to an increase in the intensity of the 515 nm peak of the phosphor and yields more increase in the peak intensity at pH 3.9 being the isoelectric point of the phosphor solution.