Effects of the pH Level on the Phosphor Characteristics of Zn2SiO4:Mn2+Coated with SiO2Nanoparticles

We report a green phosphor Zn2SiO4:Mn2+ with a surface modified by coating SiO2 nanoparticles. The phosphor was coated with SiO2 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 SiO2 nano-particles are coated uniformly on the surface of phosphors at pH 3.9. The surface coating of SiO2 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.