Control of crystal structure and performance evaluation of multi-piezo material of Li_1−xNa_xNbO₃:Pr³⁺

抄録

Piezoelectric LiNbO₃:Pr³⁺ has recently attracted attention as a so-called multi-piezo material, exhibiting simultaneously piezoluminescence and piezoelectricity. In order to investigate and improve the performance of piezoluminescence and piezoelectricity in the newly found multi-piezo material LiNbO₃:Pr³⁺, a systematic study has been carried out on both the crystal structural stability and the correlated multi-piezo performance through structure control between LiNbO₃ and NaNbO₃. Full set samples of Li_1−xNa_xNbO₃:Pr³⁺ (x = 0–1) with various Li/Na ratios were synthesized, and the crystal structure, piezoluminescence performance, piezoelectric property d₃₃, and their correlations were systematically investigated. We found that four crystal phases, LiNbO₃-R3c, NaNbO₃-R3c, NaNbO₃-P2₁ma, NaNbO₃-Pbma, can exist stably with co-existence in Li_1−xNa_xNbO₃:Pr³⁺ by controlling the Li/Na ratio. A strong correlation between piezoluminescence and piezoelectric properties was verified. Furthermore, the highest piezoluminescence intensity and piezoelectric constant were realized near the phase boundary of NaNbO₃-R3c and NaNbO₃-P2₁ma, demonstrating the crystal structure control as a promising technology to engineer multi-piezo materials.