Luminescence is already exploited for large scale applications such as light emitting diodes (LEDs), optical fibres and lasers. Luminescence is traditionally tuned via chemical methods, e.g. by changing the type and concentration of lanthanide ions, co-doping, or changing the host matrix. However, photoluminescence emission can also be modulated by the application of physical stimuli, with a significant application potential for light sources with variable colour and intensity, optical memories, switches and sensors.
The goal of our work is the fabrication of ferroelectric ceramic materials whose photoluminescence emission, induced by the incorporation of small amounts of rare earth ions in the crystal lattice, can be modulated in intensity or colour, by the application of external physical stimuli, such as a temperature variation, and to elucidate the fundamental mechanisms behind the process. This has been recently proved by our group in europium-doped (1-x)BaTiO3 – xBaZrO3 (BZT, x = 0-1) [1], exploiting the different polar order encountered by changing both temperature and composition.
Here, we present our results on several compositions in the (1-x)Na0.5Bi0.5TiO3 – xBaTiO3 (BNBT, x = 0-0.07) system, doped with Eu3+ and Tb3+ ions. Co-doping was also explored. The polar order of BNBT can be modified by changing the composition, x. The powders were prepared by conventional solid state synthesis, followed by isostatic pressing and sintering in air. The structural, microstructural, dielectric characterisation and preliminary studies of the photoluminescence properties of the ceramics as a function of temperature are reported, with the final aim to correlate composition, dielectric and photoluminescence properties.
References. [1] G. Canu et al., Scientific Reports 9, 1–11 (2019).
Acknowledgements. This work was carried out in the framework of the project MODULA, funded by the “Fondazione Compagnia di San Paolo”.