Abstract:

Sm³⁺ doped (Bi_0.5Na_0.5)TiO₃ lead-free piezoelectric ceramics were fabricated by the conventional solid-state reaction method. Phase and crystallinity of the synthesized materials were investigated by X-ray diffraction (XRD). The influences of the Sm³⁺ dopant concentration, sintering temperature and charge compensation on photoluminescence properties were systematically investigated. The results showed that the (Bi_0.5Na_0.5)TiO₃ ceramics realized red-green emission by additives of Sm³⁺ ions, and the excitation bands were well adaptable to the emission band of commercial blue light-emitting diodes. The emission intensities were strongly dependent on the dopant concentration and sintering temperature with the optimal value at 0.015 mol and 1100℃ , respectively. The enhanced luminescence was observed for the Li⁺, Na⁺ and K⁺ doped compositions as compensators compared to the host matrix with only Sm³⁺ ions, indicating that host activator energy transfer of Sm³⁺ could be responsible for this enhancement. Among the compensators of Li⁺, Na⁺ and K⁺ ions, the K⁺ compensated (Bi_0.5Na_0.5)TiO₃-Sm³⁺ samples showed the remarkable improvement in photoluminescence properties. Hence, the Sm³⁺ doped (Bi_0.5Na_0.5)TiO₃ ceramics as a multifunctional material may have significantly technological promise for optical-electro integration devices.

Key words: lead-free piezoelectric ceramics, blue light-emitting diodes (LED), multifunctional material