Multifunctional Ceramics Research Articles

Rare-earth doped (K0.5Na0.5)NbO3 multifunctional ceramics

Rare-earth elements Dy3+, Er3+, Eu3+ and Pr3+-doped (K0.5Na0.5)NbO3 ceramics were prepared by traditional solid-state sintering method. The structure, piezoelectric, ferroelectric and photoluminescence properties of the samples were investigated. All ceramics possessed orthorhombic perovsktie structures at room temperature without impurity phases. The ceramics were well sintered and displayed considerably dense microstructure and inhomogeneous grain size distributions. Good ferroelectricity could be realized in the proposed compositions. All KNN-RE ceramics exhibited photoluminescence effects. The KNN-Pr sample showed little degradation in both switchable polarization and the converse piezoelectric coefficients d 33* after 105 switching cycles, meanwhile, it had the highest photoluminescence intensity. The work provides an alternative routine to develop new multifunctional materials.

(Pb,Sm)(Zr,Sn,Ti)O3 Multifunctional Ceramics with Large Electric‐Field‐Induced Strain and High‐Energy Storage Density

Recently, the progress of integrated electronics has led to a strong demand for materials and devices with multiple functions. In this study, we achieved Pb0.985Sm0.01 (Zr0.64Sn0.28Ti0.08)O3 (PSZST) multifunctional ceramics which showed simultaneously large electric‐field‐induced strain (0.63%) and high recoverable energy density (1.743 J/cm3) at room temperature. Moreover, the strain and recoverable energy density exhibited a slight frequency fluctuation in the frequency range of 1–10 Hz. Their variations were less than 8% and 1.3% and the values were all higher than 0.58% and 1.722 J/cm3, respectively. The large strain, high‐energy density, and their good frequency stability in a wide range indicate that the PSZST ceramic is quite promising for application in multifunctional devices.

Thermally stable ferroelectricity and photoluminescence in Sm-doped 0.8(Bi0.5Na0.5)TiO3-0.2SrTiO3 ferroelectric ceramics

Reddish orange-emitting 0.8Bi0.5Na0.5TiO3-0.2SrTiO3-xSm ferroelectric ceramics were prepared by the conventional solid-state reaction route, and their electrical and optical temperature stability were also investigated. Temperature-dependent measurement of polarization revealed that the addition of Sm3+ ion significantly improved their thermal stability of ferroelectric properties. Temperature-dependent photoluminescent spectra showed that the 0.8Bi0.5Na0.5TiO3-0.2SrTiO3-xSm multifunctional ceramics exhibit well thermal stability of photoluminescence in the temperature range from 20°C to 160°C, which is superior to the thermal stability of the KBaPO4:Sm phosphors.

Strong luminescence and high piezoelectric properties in Pr-doped (Ba0.99Ca0.01)(Ti0.98Zr0.02)O3 multifunctional ceramics

(Ba0.99Ca0.01)(Ti0.98Zr0.02)O3 (BCZT) and Pr-doped samples (Pr0.002Ba0.988Ca0.01)(Ti0.98Zr0.02)O3 (BCZT-A) as well as 0.998(Ba0.99Ca0.01)(Ti0.98Zr0.02)O3-0.002PrO1.5 (BCZT-W) lead-free piezoelectric ceramics were prepared by conventional solid state reaction method. The structural, dielectric, piezoelectric, ferroelectric and luminescence properties of the Pr-doped BCZT ceramics were systematically studied. The orthorhombic-tetragonal (O–T) phase transition temperature decreased obviously, while Curie temperature (TC) maintained at 118 °C for both of the Pr-doped BCZT ceramics. The BCZT-A ceramics exhibited the best piezoelectric properties (d33 = 344 pC/N) and ferroelectric properties (Pr = 13.042 μC/cm2). Meanwhile, desired luminescence properties (bright reddish-orange light, emission peak centered at 649 nm) were obtained under an excitation of 448 nm at room temperature for BCZT-A and BCZT-W ceramics. The luminescence properties of the BCZT-A ceramics were better than those of the BCZT-W ceramics. Asymmetric structure, coexistence of orthorhombic and tetragonal phases at room temperature and less oxygen vacancies exhibited in BCZT-A ceramics could result in the improved piezoelectric properties and luminescence properties simultaneously. These results suggest that the BCZT-A ceramics have potential application as a multifunctional device by integrating its excellent electrical and luminescence properties.

Strong red emission and enhanced ferroelectric properties in (Pr, Ce)-modified Na0.5Bi4.5Ti4O15 multifunctional ceramics

Bismuth layer-structured ferroelectric (BLSFs) ceramics of Na0.5Bi4.5−x (Pr0.5Ce0.5) x Ti4O15 (NBT-x(Pr, Ce), x = 0.000, 0.004, 0.008, 0.012) were prepared by a conventional solid-state reaction method, and the influence of (Pr, Ce) additive on the ferroelectric, dielectric, and photoluminescence properties of samples were investigated. It is found that all the samples have a bismuth oxide layered structure with a dense microstructure. After (Pr, Ce) doping, the samples showed a bright red photoluminescence. The sharp excitation peaks around 449, 480 and 491 nm correspond to the 3H4 → 3P2, 3H4 → 3P1 and 3H4 → 3P0 transition, respectively. Upon the excitation of 492 nm light at room temperature, samples show two emission bands located at 611 and 656 nm, respectively. The strong red emission band centered at 611 nm is attributed to 1D2 → 3H4 transition, and the weak red emission located 656 nm is due to the 1D2 → 3H5 transition. In addition, it is an intrinsic ferroelectric and piezoelectric material, and the enhanced ferroelectric properties were obtained by (Pr, Ce) doping. At x = 0.004, the remnant polarization 2P r reaches 13.54 μC/cm2, together with a high Curie temperature (T c = 662 °C) and activation energy of E a = 0.83 eV. As a multifunctional material, the (Pr, Ce)-modified NBT piezoelectric ceramic may be useful in white LEDs, sensor and optical-electro integration.

Strong photoluminescence and good electrical properties in Eu-modified SrBi2Nb2O9 multifunctional ceramics

Bismuth layer-structured ferroelectric (BLSFs) ceramics of Sr1−xEux Bi2Nb2O9 (SBT-xEu, x=0.000, 0.002, 0.004, 0.006) were prepared by a conventional solid-state reaction method. All the samples have a bismuth oxide layered structure with a dense microstructure. The ferroelectric, piezoelectric, dielectric and optical properties of the ceramics were investigated. After Eu3+ doping, samples show a bright red photoluminescence upon blue light excitation of the 400–500nm. Upon the excitation of 465nm light, the materials have two intense emission bands peaking around 593nm (yellow) and 616nm (red). Meanwhile, good electrical properties with large piezoelectric constant d33 of 14pC/N and large remnant polarization 2Pr of 11.97μC/cm2 are obtained at x=0.006. Moreover, this material has a high Curie temperature (Tc=429°C) and high resistivity, which makes the material resistant to thermal depolarization up to its Curie temperature. This feature indicates that the SBN-xEu ceramics have a latent use in high temperature applications.

Temperature and concentration effects on upconversion photoluminescence properties of Ho3+ and Yb3+ codoped 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 multifunctional ceramics

Ho3+ and Yb3+ codoped lead magnesium niobate–lead titanate (PMN–PT) ceramics with various doping concentration have been fabricated by conventional solid reaction method. Under the excitation of 980nm laser, as-synthesized samples exhibit bright yellow-green upconversion (UC) luminescence. Their UC photoluminescence properties were investigated by the emission spectra with respect to various concentration of Ho3+ and Yb3+. Results show that optimal luminescent concentration was obtained in 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 ceramics codoped with 0.5mol% Ho3+ and 2mol% Yb3+ (abbreviated as 67PMN–33PT:2Yb,0.5Ho). The possible mechanism of UC emission was discussed by energy level diagrams of Ho3+ and Yb3+ ions according to the dependence of integrated intensity of UC emission bands on pumping power. Furthermore, the temperature dependence of UC emission intensity of 67PMN–33PT:2Yb,0.5Ho sample was investigated in detail in the range of 25–180°C under excitation by a 980 diode laser. According to Arrhenius formula, the fitting result of the effect of temperature on integrated intensity of emission band was coinciding well with the experiment results. It is shown that the emission intensity depends strongly on temperature, which has excellent relative sensitivity with its maximum value of 0.77%K−1 at 93°C. These indicate that the 67PMN-33PT:2Yb,0.5Ho ceramic may be useful for temperature sensing and optical-electrical devices as a multifunctional material.

Tunable photoluminescence properties of Pr3+/Er3+-doped 0.93Bi0.5Na0.5TiO3–0.07BaTiO3 low-temperature sintered multifunctional ceramics

Pr3+/Er3+-doped 0.93Bi0.5Na0.5TiO3–0.07BaTiO3 ceramics have been fabricated at a low sintering temperature of 960°C using a sintering aid of Li2CO3. The effects of energy transfer between Pr3+and Er3+on their photoluminescence properties have been investigated. Our results reveal that the down-conversion emissions of Pr3+are weakened and the lifetimes are shortened by the co-doping of Er3+. As a result, when both Pr3+and Er3+are excited simultaneously, with increasing the concentration of Er3+, the green emissions from Er3+increase but the red emissions from Pr3+decrease. Moreover, the emission color of the ceramics can be reversibly changed between red, yellow and yellowish green by using excitation sources of different wavelengths. Strong up-conversion green emissions with short lifetimes arisen from Er3+have also been observed for the ceramics under the excitation of 980nm. Owing to the Li2CO3 sintering aid, the low-temperature sintered ceramics also exhibit reasonably good ferroelectric and piezoelectric properties, and hence should be promising for multifunctional applications such as electro-optical coupling devices.

Enhanced ferroelectricity/piezoelectricity, bright blue/yellow emission and excellent thermal stability in Ca1−x(LiDy)x/2Bi4Ti4O15 lead-free multifunctional ceramics

A new lead-free solid solution of Ca1−x(LiDy)x/2Bi4Ti4O15 has been developed and prepared by a conventional solid state reaction method.

Up-conversion Luminescence, Temperature Dependence and Ferroelectric Properties in Ho3+ and Yb3+ Co-Doped Bi3TiNbO9 Multifunctional Ceramics

Bi3TiNbO9 (BTN) is an important member of the Aurivillius bismuth layer-structured ferroelectric compounds, consisting of [Bi2O2]2+ layers between which [BiTiNbO7]2- layers are inserted. Ho3+ and Yb3+ co-doped Bi3TiNbO9 (BTN) ceramics were synthesized by a conventional solid state reaction method and their up-conversion (UC) luminescence and the ferroelectric properties were investigated. A strong green emission band centered at 547 nm, two weak red emission bands centered at 657 nm and 758nm were obtained under a 980 nm laser excitation at room temperature. With the increasing of Yb3+ content, the intensity of the up-conversion luminescence increased initially and then decreased due to concentration quenching. The fluorescence intensity ratio of green UC emission centered at 547 nm and red UC emission centered at 657 nm was studied as a function of temperature in a range of 123 - 573K, and the result showed a quite good linear variation of the two emissions with temperature, which indicates that Ho3+/Yb3+ co-doped Bi3TiNbO9 multifunctional ceramic is a promising candidate for applications in optical temperature sensors.

Photoluminescence, Enhanced Ferroelectric and Dielectric Properties of Pr3+ Doped SrBi4Ti4O15 Multifunctional Ceramics

Pr doped SrBi4Ti4O15 multifunctional ceramics were prepared by a conventional sintering technique and their luminescent, dielectric and ferroelectric properties were studied. The PL spectra at room temperature indicated that the red emission was excited by the ultraviolet and blue light, revealed their potential application in white-light LED. The investigation of dielectric and ferroelectric properties showed that the integration of luminescent, electrical properties by Pr ion doping would obviously enhance the ferroelectric properties. It is believed that the multifunctional ceramics have the great potential for application use in electro-optical devices, memory and display integrated chips.

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

Multifunctional ceramics of 0.94(Bi1−xErxNa)0.5TiO3–0.06BaTiO3 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 Er3+ has no obvious influence on the crystal structure. The partial substitution of Er3+ for Bi3+ improves the piezoelectricity of the ceramic. The ceramics with x=0–0.02 possess strong ferroelectricity (Pr=26.7–29.6μC/cm2) and good piezoelectric properties (d33=146–181pC/N, kp=21.2–34.1%, respectively). After the addition of Er3+, the ceramics exhibit the characteristic up/down-conversion emission of Er3+ ions. The ceramic with x=0.032 possesses the strongest emissions at approximately 535nm and 549nm, which are attributed to 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions, respectively. The ceramics with low Er2O3 levels exhibit simultaneously strong piezoelectricity, ferroelectricity and photoluminescence and thus may have a potential application in multifunctional devices.

Multiple improvement in piezoelectricity, ferroelectricity, and fluorescence of 0.94(Bi0.984Er0.016Na)0.5TiO3–0.06BaTiO3 by optimizing sintering temperature/dwell time

Multifunctional ceramics of 0.94(Bi0.984Er0.016Na)0.5TiO3–0.06BaTiO3 were prepared by a conventional ceramic technique. The effects of sintering temperature (Ts) and dwell time (ts) on the ferroelectricity, piezoelectricity, and fluorescence of the ceramics were studied. Furthermore, the influence of poling electrical field on the up‐conversion emission intensities was also discussed. As Ts and ts increase, the grains grow larger gradually and evolve from spheroid to rectangular shape. By increasing Ts and ts, the ferroelectricity of the ceramics is improved and the remnant polarization Pr increases. The optimum sintering temperature and dwell time for the piezoelectricity of ceramics are 1200 °C and 2 h, respectively. Also, both of the sintering temperature and dwell time make an important influence on the fluorescence of the ceramics. The ceramics sintered at 1140–1160 °C for 2 h possess excellent up/down‐conversion fluorescence. The up‐conversion emission intensity of the ceramics is further enhanced by optimizing poling electric field. This work develops a kind of multifunctional material that simultaneously possesses good ferroelectricity/piezoelectricity and excellent up/down‐conversion fluorescence by optimizing sintering temperature and dwell time.

New ways to synthesize multifunctional ceramics La2 - x Sr x NiO4

A study was made of specific features of the formation of multifunctional ceramics La2 - xSrxNiO4 in thermal decomposition of carboxylate precursor complexes of several types. Pyrolysis of organics–salt composites is initiated by catalytic decarboxylation under the action of a d-element (Ni) to form metal oxides in the active state. It was shown that the synthesis of solid solutions La2 - xSrxNiO4 from carboxylate precursors occurs by single-stage thermolysis using any carboxylic acid or its salt.

Оптимизация процесса напыления износостойких покрытий на основе многофункциональной оксидной керамики

Оптимизация процесса напыления износостойких покрытий на основе многофункциональной оксидной керамики

Технология получения композиционного материала на основе многофункциональной оксидной керамики

Технология получения композиционного материала на основе многофункциональной оксидной керамики

Enhanced piezoelectricity and photoluminescence in Dy-doped Ba0.85Ca0.15Ti0.9Zr0.1O3 lead-free multifunctional ceramics

Lead-free multifunctional ceramics of Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3-x mol% Dy have been prepared by an ordinary sintering method and the effects of Dy 2 O 3 doping on structure, piezoelectric, ferroelectric and photoluminescent properties of the ceramics have been studied. The ceramics possess a single phase perovskite structure. The grain growth of the ceramics is prohibited and the ferroelectric–paraelectric phase transition at TC becomes more diffusive after the addition of Dy 2 O 3. Dy 2 O 3 doping improves the piezoelectricity of the ceramics and the optimal piezoelectric properties d33 = 335 pC/N is obtained at x = 0.5. The addition of 2 mol% Dy enhances the photoluminescent properties of the ceramics and strong emissions at ∼ 478 nm and ∼ 575 nm are observed. Our study shows that the ceramics with low Dy 2 O 3 levels exhibit simultaneously the strong piezoelectricity, ferroelectricity and photoluminescence and may have a potential application in mechano-electro-optic integration and coupling device.

Structure, Ferroelectric and Photoluminescence Properties of Eu-Doped CaBi4Ti4O15 Multifunctional Ceramics

Lead-free multifunctional ceramics of CaBi4−xEuxTi4O15 were prepared by a traditional solid state method, and the effects of Eu doping on structure, ferroelectric, piezoelectric and photoluminescence properties of the ceramics were investigated. All the ceramics possessed typical bismuth layer structure with m = 4, belonging to orthorhombic symmetry, and no secondary phase was detected. The plate-like grains were observed in all the ceramics, and the grain growth was slightly inhibited after the addition of Eu. Saturated polarization hysteresis loops were observed for all the ceramics, and the remanent polarization Pr decreased with Eu doping. The Eu-doped ceramics had a sharp excitation band centered at 465 nm due to the f–f transition from the 7F0 ground state to the 5D2 excited state of Eu3+. Under the excitation by 465 nm light, the main emission peaks located at 595 nm and 616 nm were obtained, which corresponds to the transition of 5D0–7F1, 5D0–7F2 levels in Eu3+, respectively. Our study shows that CaBi4Ti4O15 ceramics may be a promising multifunctional material for potential applications in optical-electro integration devices.

Enhanced piezoelectricity and photoluminescence in Dy-modified 0.94(Bi1−x Dy x )0.5Na0.5TiO3–0.06BaTiO3 lead-free multifunctional ceramics

Lead-free 0.94(Bi1−xDyx)0.5Na0.5TiO3–0.06BaTiO3 ceramics were prepared by an ordinary sintering method and their 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 pC/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.

Improved ferroelectric/piezoelectric properties and bright green/UC red emission in (Li,Ho)-doped CaBi4Ti4O15 multifunctional ceramics with excellent temperature stability and superior water-resistance performance.

Multifunctional materials based on rare earth ion doped ferro/piezoelectrics have attracted considerable attention in recent years. In this work, new lead-free multifunctional ceramics of Ca1-x(LiHo)x/2Bi4Ti4O15 were prepared by a conventional solid-state reaction method. The great multi-improvement in ferroelectricity/piezoelectricity, down/up-conversion luminescence and temperature stability of the multifunctional properties is induced by the partial substitution of (Li0.5Ho0.5)(2+) for Ca(2+) ions in CaBi4Ti4O15. All the ceramics possess a bismuth-layer structure, and the crystal structure of the ceramics is changed from a four layered bismuth-layer structure to a three-layered structure with the level of (Li0.5Ho0.5)(2+) increasing. The ceramic with x = 0.1 exhibits simultaneously, high resistivity (R = 4.51 × 10(11)Ω cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 °C), strong ferroelectricity (Pr = 9.03 μC cm(-2)) and enhanced luminescence. These behaviours are greatly associated with the contribution of (Li0.5Ho0.5)(2+) in the ceramics. Under the excitation of 451 nm light, the ceramic with x = 0.1 exhibits a strong green emission peak centered at 545 nm, corresponding to the transition of the (5)S2→(5)I8 level in Ho(3+) ions, while a strong red up-conversion emission band located at 660 nm is observed under the near-infrared excitation of 980 nm at room temperature, arising from the transition of (5)F5→(5)I8 levels in Ho(3+) ions. Surprisingly, the excellent temperature stability of ferroelectricity/piezoelectricity/luminescence and superior water-resistance behaviors of piezoelectricity/luminescence are also obtained in the ceramic with x = 0.1. Our study suggests that the present ceramics may have potential applications in advanced multifunctional devices at high temperature.