Blue afterglow emission of glass-ceramics synthesized by melting mixture of ZrO2:Ti, K2CO3, and H3BO3

This study investigates the enhancement of blue afterglow emission from ZrO2:Ti heat treatment at 1500 °C in air with raw ZrO2 containing 1000 ppm TiO2. The afterglow time of KZrB4O8.5, which was melt heat-treated with ZrO2:Ti heat-treated at 1500 °C, K2CO3, and H3BO3 at 1300 °C in air, was extended by approximately 2.5 times. XRD analysis of ZrO2:Ti revealed only monoclinic peaks, while that of KZrB4O8.5 with a glass-ceramic composition displayed monoclinic peaks and a halo. In the XPS analysis of ZrO2:Ti and KZrB4O8.5 with a glass-ceramic composition, the presence of Zr4+ and a small amount of Zr3+ was observed, while that of Zr2+ could not be confirmed. SEM observations revealed that ZrO2:Ti was composed of uniformly sized grains of approximately 0.5 μm size, whereas KZrB4O8.5 with a glass-ceramic composition exhibited coarsened grains of approximately 10 μm size. The afterglow decay curves of KZrB2O5.5, KZrB3O7.0, KZrB5O10.0, and KZrB6O11.5 with a glass-ceramic composition with varying B content in KZrB4O8.5 with a glass-ceramic composition were measured, and based on the results obtained, the afterglow time increased with an increase in the coarse grain size.