Control of crystal structure and performance evaluation of multi-piezo material of Li1−xNaxNbO3:Pr3

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 Li1−xNaxNbO3: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 Li1−xNaxNbO3: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.