Piezoelectric ceramic materials is one of the most important functional material and has been widely used in actuator, sonar and energy converter. However, most of commercial piezoelectric ceramics are Pb-containing materials. The strong toxicity of Pb O has caused serious environment problems. Therefore, many science researchers have focused on developing lead-free ceramic materials with excellent properties. On the other hand, with the development of the miniaturization and mulfifunctionalization, rare earth-doped ferroelectric-photoluminesct multifunction materials have attraction considerable attention in recent years.In this thesis, we developed and prepared rare earth(Dy3+, Sm3+, Tm3+)-doped BNT based ceramics by a conventional ceramic technique, and the structure ferroelectric, piezoelectric and photoluminescence properties of the ceramics were systematically inveatiagated. The main results are listed as following:(1)Lead-free ceramics of 0.94(Bi1-xDyx)0.5Na0.5TiO3-0.06 Ba TiO3 were prepared by an ordinary sintering method and their structure, ferroelectric, piezoelectric and photoluminescent properties were studied. All the ceramics possess a pure perovskite structure with the coexistence of the rhombohedral and tetragonal phase. The partial substitution of Dy3+ for Bi3+ enhanced effectively the piezoelectricity of the materials. The optimum piezoelectricity is obtained at x = 0.025, giving d33 = 190 p C/N and kP = 37.2%, respectively. After the addition of Dy3+, excellent photoluminescence of the ceramics is induced. The Dy-doped ceramics exhibit strong emissions at 478 nm(blue) and 575 nm(yellow), corresponding to 4F9/2 ' 6H15/2 and 4F9/2 ' 6H13/2 of Dy3+ transitions, respectively. The optimum photoluminescence of the ceramics is reached at x = 0.025. The ceramics with the doping of 2.5 mol% Dy3+ exhibit simultaneously good piezoelectricity, strong ferroelectricity and excellent photoluminescence, suggesting a promising application in the electro-optic devices.(2)0.94(Bi1-xSmxNa)0.5TiO3-0.06 Ba TiO3(x = 0-0.05) lead-free ceramics were synthesized by a conventional solid-state reaction route and the microstructure, piezoelectric, ferroelectric and photoluminescent properties of the ceramics were investigated. The ceramics can be well sintered at 1200 °C for 2 h. All the ceramics exhibit a pure perovskite structure with the coexistence of rhombohedral and tetragonal phases. After the addition of a small amount of Sm3+(x ≤ 0.035), the piezoelectricity is enhanced with d33 increasing from 147 p C/N to 172 p C/N, while excess Sm3+(x = 0.035–0.05) degrades significantly the piezoelectricity with d33 decreasing from 172 p C/N to 18 p C/N. Under the excitation of 406 nm, three emission peaks located at 563 nm(4G5/2-6H5/2), 597 nm(4G5/2-6H7/2), and 645 nm(4G5/2-6H9/2) are observed. Under the emission of 564 nm, the ceramics with Sm3+ exhibit five excitation peaks at 407, 420, 464, 440 and 479 nm corresponding to 6H5/2-4F7/2, 6H5/2-(6P, 4P)5/2, 6H5/2-4G9/2, 6H5/2-4I11/2,13/2 and 6H5/2-4M15/2, respectively. Both the intensities of the 4G5/2'6H5/2 emission peak and 6H5/2'4F7/2 excitation peak first increase and then decrease with increasing x. And the highest intensity was obtained at x = 0.035. The average lifetime τav decreases from 1.0869 ms to 0.7850 ms with increasing x.(3)Lead-free ceramics of(Bi1-xTmx)0.5(Na0.85K0.15)0.5TiO3 were prepared by a conventional ceramic technique and the effects of Tm doping on the microstructure, ferroelectric, piezoelectric and photoluminescent properties were studied. All the ceramics possess a pure perovskite structure and Tm3+ diffuses into the Bi0.5(Na0.85K0.15)0.5TiO3 lattices to form a solid solution with the coexistence of the rhombohedral and tetragonal symmetry. The addition of Tm3+ leads to the significant change in the grain morphology and size for the(Bi1-xTmx)0.5(Na0.85K0.15)0.5TiO3. The grain size increases and then gradually decreases with the increasing x. The partial substitution of Tm3+ for Bi3+ enhanced effectively the piezoelectricity, giving d33 = 155 p C/N at x = 0.04. While the excess Tm3+ degrades significantly the piezoelectricity. Under the excitation of 980 nm, the Tm3+-doped ceramics shows three up-conversion emission peaks at 486nm、550nm and 649 nm, which can be attributed to the 1G4'3H6, 1G4'3F4 and 3 F 23'3H6 transitions of Tm3+. |