Enhanced piezoelectricity, bright up-conversion and down-conversion photoluminescence in Er3+ doped 0.94(BiNa)0.5TiO3–0.06BaTiO3 multifunctional ceramics

Abstract Multifunctional ceramics of 0.94(Bi 1− x Er x Na) 0.5 TiO 3 –0.06BaTiO 3 have been fabricated by an ordinary sintering technique, and their structure, piezoelectricity, ferroelectricity and photoluminescence have been studied. The rhombohedral and tetragonal phases co-exist in the ceramics with x = 0–0.036 and the concentration of Er 3+ has no obvious influence on the crystal structure. The partial substitution of Er 3+ for Bi 3+ improves the piezoelectricity of the ceramic. The ceramics with x = 0–0.02 possess strong ferroelectricity ( P r = 26.7–29.6 μC/cm 2 ) and good piezoelectric properties ( d 33 = 146–181 pC/N, k p = 21.2–34.1%, respectively). After the addition of Er 3+ , the ceramics exhibit the characteristic up/down-conversion emission of Er 3+ ions. The ceramic with x = 0.032 possesses the strongest emissions at approximately 535 nm and 549 nm, which are attributed to 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions, respectively. The ceramics with low Er 2 O 3 levels exhibit simultaneously strong piezoelectricity, ferroelectricity and photoluminescence and thus may have a potential application in multifunctional devices.