Abstract

When activated by Dy3+, Na0.25K0.25Bi0.50TiO3 (NKBT), piezoelectric powders show strong luminescence in the blue and yellow spectral range. Emissions of this material can be effectively utilized for both luminescence intensity ratio and lifetime-based readouts of temperature. Photoluminescence measurements over a temperature range of 293–483 K show that the luminescence intensity ratio temperature readout has maximal relative sensitivity of 1.93% K−1 at 380 K, while the relative sensitivity of the lifetime temperature readout reaches 1.1% K−1 at 480 K. For this study, materials were synthesized by a solid-state reaction using TiO2, Bi2O3, Na2CO3, K2CO3 and Dy2O3 as precursors. X-ray diffraction measurements showed that the NKBT sample crystallized in the A-site substituted distorted perovskite rhombohedral structure (R3c symmetry). The photoluminescence spectra showed characteristic emission bands of Dy3+ ions centered at 457 nm (4I15/2 → 6H15/2), 478 nm (4F9/2 → 6H15/2), 574 nm (4F9/2 → 6H13/2) and 663 nm (4F9/2 → 6H11/2). The ratio of emissions from 4F9/2 and 4I15/2 excited states to the 6H15/2 ground state was used as a luminescence intensity ratio indicator of temperature, while the decay of emission from 4F9/2 → 6H13/2 transition was used as a lifetime indicator of temperature. CIE coordinates x = 0.326 and y = 0.361 calculated from room temperature emission spectra show the perspective of this material for use in white light emission devices.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call