Surface modification of KBaBP2O8:Eu3+ phosphors by Al-doped ZnO coating

Abstract KBaBP 2 O 8 :Eu 3+ phosphors for white light-emitting diodes (w-LEDs) were prepared by high temperature solid-state reaction. Surface modification of these phosphors was carried out by coating transparent conductive films of Al-doped ZnO (AZO) through a sol–gel method. Phase compositions, morphologies, photoluminescence spectra and zeta potential of KBaBP 2 O 8 :Eu 3+ phosphors were examined before and after AZO coating. It was found that surface modification with appropriate AZO coating led to an increase in the luminance intensity but a decrease in the zeta potential of the phosphors dispersed in deionized water. The thermal stability was studied by the temperature dependent photoluminescence spectra for temperature ranging from 30 to 250 °C. The AZO-coated phosphors have a superior thermal quenching property compared to the pristine ones. It is thus believed that coating with a transparent conductive AZO film is an effective way to reduce the surface charge buildup and to enhance the thermal stability of phosphors.