UV C luminescence of a modified zirconium silicate framework upon cathode ray and VUV excitation

Abstract

This work concerns the cathode (CL) and photoluminescence (PL) of silicates according to the compositions K2MSi2O7 (M= Zr, Hf) and SrZrSi2O7. It also relates to the band gap determination of K2ZrSi2O7 and SrZrSi2O7, which were determined to 5.6 eV for the former and 5.0 eV for the latter compound. Modification of K2ZrSi2O7 by the substitution of Zr by Hf shows that the incorporation of 20% Hf improves the PL of the material, while a complete replacement of Zr4+ by Hf4+ entirely quenches the charge-transfer based luminescence process. Quenching of the luminescence is also observed for the incorporation of Ln(3+) (Ln= Ce, Pr, Tb). The emission band of K-2(Zr, Hf)Si2O7 is nicely located in the UV-C range yielding an overlap with the germicidal activation curve (GAC) close to that of Lu2Si2O7: Pr, i.e. of about 55%. This finding brands the material as an interesting compound for radiation sources to be used in disinfection devices.