Splendid cryogenic optical thermometry and rewritable photomemory based on the up-conversion luminescence of K0.5Bi0.5TiO3: Er/In ceramic

Bifunctional luminescence materials have aroused much concern due to their wide application and high utilization. In this work, we have successfully integrated bright green up-conversion luminescence of K0.5Bi0.5TiO3 (KBT): Er/In ceramics with potential applications on cryogenic optical thermometry and photomemory. By employing the fluorescence intensity ratio based on thermally coupled levels of Er3+: 2H11/2 / 4S3/2, the splendid low-temperature sensing properties are demonstrated as the maximum relative sensitivities are 7.14% K-1 and 8.73% K-1 at 137 K for KBT: Er and KBT: Er/In ceramics, respectively. Moreover, the reversible photochromism performance could be triggered by the 365 nm irradiation and vanished by thermal stimulation at 150 ℃. Remarkably, the coupling of up-conversion luminescence and photochromism performance prospers the promising application on rewritable photomemory. For KBT: Er/In ceramic, the emission intensity could be reduced by 76.59% after coloration and restored to its original value after bleaching. In order to evaluate the practicability of applying on photomemory, a reversible experiment was designed and successfully executed. It is believed that the KBT: Er/In bifunctional ceramics can be a great candidate for low-temperature sensing and optical information storage devices.