Dingquan Xiao

Sichuan University, Hua-yang, Sichuan, China

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Publications (296)611.5 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BiFeO3 (BFO) thin films doped differently with 5 mol% Mn3+ and 5 mol% Mn2+ were prepared on (111)Pt/Ti/SiO2/Si substrates by a sol-gel method with rapid thermal annealing. Systematic analyses about the two different doping effects and their underlying mechanisms were performed. Pure and doped BFO films were well crystallized in perovskite structure, whilst doping of Mn3+ and Mn2+ resulted in slight distortion in the lattice structure. After doping, smaller grain size, diminished structural defects and denser microstructure were confirmed. Both Mn3+ and Mn2+ dopants could reduce the concentration of oxygen vacancies in BFO films, whereas Mn3+doping exhibited better ability. As a result, the Mn3+ doped film showed the highest dielectric permittivity among those three samples, εr=105 at 100 kHz; meanwhile, the Mn3+ doped film showed a superior 2Pr value of 79.5 µC/cm2, compared to 63.2 µC/cm2 for the Mn2+ doped film and unachievable intrinsic ferroelectric polarizations in the undoped BFO film because of high leakage contribution. The leakage current density in medium/high electric field region was dramatically decreased by Mn doping, accompanied with a change of conduction mechanism from the space charge limited conduction to the Schottky mechanism.
    Ceramics International 04/2015; DOI:10.1016/j.ceramint.2015.03.269 · 2.09 Impact Factor
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    ABSTRACT: Ca0.92(Li,Ce)0.04Bi2Nb2−x Wx O9 (x = 0.01–0.06) high-temperature piezoceramics were prepared by a conventional solid-state sintered method, and effects of W content on their piezoelectric properties were studied. All samples possess a pure Aurivillius-type structure, showing that Li, Ce, and W dopants have well diffused into the CaBi2Nb2O9 lattice to form a solid solution. The doping with W slightly decreases the Curie temperature (T C) of the ceramics. In addition, the excellent electrical properties (e.g., d 33 ~ 16.1 pC/N, k p ~ 9.58 %, Q m ~ 4,767) and a high Curie temperature (e.g., T c ~ 925 °C) are simultaneously obtained in the ceramics with x = 0.04, together with an enhanced thermal stability of
    Applied Physics A 04/2015; 119(1). DOI:10.1007/s00339-014-8972-4 · 1.69 Impact Factor
  • Bo Wu, Dingquan Xiao, Jiagang Wu, Qian Gou, Jianguo Zhu
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    ABSTRACT: Lead-free piezoelectric ceramics of (Ba0.98Ca0.02)(Ti0.94Sn0.06)O3–x wt% ZnO (BCTS–xZnO) were synthesized by the conventional solid-state method. The microstructures and the electrical properties of BCTS–xZnO ceramics were systematically studied in the composition range of 0 ≤ x ≤ 0.20. It was found that the sintering temperature of BCTS ceramics was gradually decrease using ZnO as a sintering aid, and the addition of ZnO did not change the tetragonal phase structure of the ceramics. The BCTS–xZnO ceramics with x = 0.10 sintered at a lower temperature of ~1,350 °C for 3 h demonstrated an optimum electrical behavior: d 33 ~ 428 pC/N, k p ~ 53.3 %, 2P r ~ 24 μC/cm2, and 2E c ~ 3.0 kV/mm. As a result, the BCTS–xZnO ceramic is a promising candidate for lead-free piezoelectric ceramics.
    Journal of Materials Science Materials in Electronics 04/2015; 26(4). DOI:10.1007/s10854-015-2687-y · 1.97 Impact Factor
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    ABSTRACT: Lead-free piezoelectric ceramics have attracted considerable attention owing to their environmental friendliness and good electrical properties. Here the new (1-x)K0.5Na0.5NbO3–x(0.15Bi0.5Na0.5TiO3–0.85Bi0.5Na0.5ZrO3) [(1-x)KNN–x(BNT–BNZ)] ternary lead-free piezoelectric ceramics synthesized by conventional solid sintering method were reported. The microstructure and electrical properties of (1-x)KNN–x(BNT–BNZ) ternary ceramics were systematically investigated, and the ceramics with x=0.06 possess the enhanced piezoelectric properties and a high TC (e.g., d33~318 pC/N, kp~0.43, and TC~326 oC), which are mainly ascribed to the involved R-T phase boundary. It is believed that such a ceramic system is one of the promising candidates in the field of lead-free piezoelectric ceramics.
    RSC Advances 03/2015; DOI:10.1039/C4RA16780E · 3.71 Impact Factor
  • Jiagang Wu, Dingquan Xiao, Jianguo Zhu
    Chemical Reviews 03/2015; 115(7). DOI:10.1021/cr5006809 · 45.66 Impact Factor
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    ABSTRACT: Here we report a strong piezoelectric activity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free ceramics by designing different phase boundaries. The phase boundaries concerning rhombohedral-orthorhombic-tetragonal (R-O-T) and rhombohedral-tetragonal (R-T) multiphase coexistence were attained by changing BKZS and Sn contents and then were identified by the X-ray diffraction patterns as well as temperature-dependent permittivity and ν1 Raman modes associated with BO6 perovskite octahedron. A high strain (strain = 0.21-0.28% and d33* = 707-880 pm/V) and a strong piezoelectric coefficient (d33 = 415-460 pC/N) were shown in the ceramics located at the multiphase coexistence region. The reported results of this work are superior to that (d33* ∼ 570 pm/V and d33 ∼ 416 pC/N) of the textured (K,Na,Li)(Nb,Ta,Sb)O3 ceramics [Nature 2004, 432, 84]. We believe that the material system of this work will become one of the most promising candidates for piezoelectric actuators.
    ACS Applied Materials & Interfaces 03/2015; DOI:10.1021/acsami.5b00151 · 5.90 Impact Factor
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    ABSTRACT: Modified Ba0.67Sr0.33TiO3 (BST) thin films were deposited on Pt/Ti/SiO2/Si substrates using RF magnetron sputtering. By optimizing the deposition temperature (Td), the dielectric and ferroelectric properties of BST films were improved. The onset of crystallization of the BST films was observed at about 600 °C, beyond which there was an increase in grain size with further increasing Td up to 700 °C. The better crystallized film deposited at 700 °C with a thickness of 670 nm shows a polycrystalline and dense structure, a dielectric constant ( ) =953.40(at 100 kHz), and a remanent polarization (2Pr)=23.87 μC/cm2. The dielectric tunability at 1 MHz increases as Td increases, and reaches the highest value of 55.40% for an applied field of 770 kV/cm at the highest Td of 700 °C. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electric performance analysis also indicate that deposition temperature during growth strongly affects the microstructure of BST films. This in turn influences the dielectric, ferroelectric and tunable behavior of BST films.
    Ceramics International 03/2015; DOI:10.1016/j.ceramint.2015.03.158 · 2.09 Impact Factor
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    ABSTRACT: (LiCe)-modified (NaBi)0.48[ ]0.04Bi2Nb1.97W0.03O9 ceramics were prepared by conventional solid state sintering method, and the effect of doping on the electrical properties was studied. The dense microstructure with a high relative density ρrd (>98.12%) was well developed in this material system, presenting a typical Aurivillius phase structure. The Curie temperature (TC) gradually increases from 766 °C to 776 °C with increasing (LiCe) content, and moreover the addition of (LiCe) significantly increases the piezoelectric constant (d33). The (NaBi)0.43(LiCe)0.05[ ]0.04Bi2Nb1.97W0.03O9 ceramics exhibit optimum electrical properties (e.g., d33 ∼ 26.1 pC/N, kp ∼ 10.5%, and Qm ∼ 3209), together with a relatively high TC (∼771 °C) and good thermal stability until 750 °C. These results indicate that this ceramic is a promising candidate for high-temperature piezoelectric applications.
    Journal of Alloys and Compounds 03/2015; 625:113-117. DOI:10.1016/j.jallcom.2014.11.107 · 2.73 Impact Factor
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    ABSTRACT: In this work, (1 - x)(K0.48Na0.52)(Nb0.95-y-zTazSby)O3-xBi0.5(Na0.82K0.18)0.5ZrO3, {abbreviation: KNNST-BNKZ-x-y-z} lead-free piezoceramics were prepared by a conventional solid-state reaction method, and the composition dependence of their phase structures and electrical properties was systematically discussed. Doping with Sb(5+), Ta(5+), and BNKZ plays an important role on the phase boundaries as well as piezoelectric activity. A three-phase coexistence involving rhombohedral-orthorhombic-tetragonal (R-O-T) phases was observed in the ceramics with 0.0325 ≤ x ≤ 0.05, 0.035 ≤ x ≤ 0.065, 0.05 ≤ z ≤ 0.08, indicating that doping with BNKZ, Ta(5+), and Sb(5+) can induce the formation of such a phase boundary by simultaneously increasing TR-O and decreasing TO-T. Enhanced piezoelectric behavior was observed in the ceramics located in the composition region of the R-O-T phase boundary, and a high d33 value of 400 pC N(-1) can be attained by refining their compositions (e.g., x = 0.0325, y = 0.035, and z = 0.05), together with a high TC value of ∼240 °C. Of particular interest is that a large electric field-induced strain of 0.18% (Smax/Emax = 706 pm V(-1)) was also found in the ceramics with x = 0.0325, y = 0.035, and z = 0.05 under a low electric field of 2.5 kV mm(-1). As a result, the piezoelectric activity as well as the strain can be operated in the material system by refining x, y, and z content.
    Dalton Transactions 02/2015; 44(10). DOI:10.1039/c4dt04038d · 4.10 Impact Factor
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    ABSTRACT: In this work, new (K, Na)NbO3 ternary system {e.g., (1−x) (0.96K0.48Na0.52(1+3/995)NbO3-0.04Bi0.5K0.5ZrO3)-xBaZrO3} lead-free piezoceramics have been prepared by the conventional solid state sintering method, and effects of BaZrO3 contents on their microstructure and electrical properties were investigated in detail. The rhombohedral-orthorhombic and orthorhombic-tetragonal phase coexistence has been found in the ceramics with the composition range of 0.0125 < x ⩽ 0.02, and then the ceramics with x = 0.0175 exhibit enhanced electrical properties (e.g., d33 = 305 pC/N, kp = 49.5%, εr = 1945, tan δ = 3.9%, Pr = 22.5 μC/cm2, and EC = 10.2 kV/cm). In addition, such a ceramic possesses a high Curie temperature (TC = 300 °C). These results show that this material should be one of the most promising lead-free candidates for piezoelectric applications.
    Journal of Alloys and Compounds 01/2015; 619:560-563. DOI:10.1016/j.jallcom.2014.09.032 · 2.73 Impact Factor
  • Ting Zheng, Jiagang Wu, Dingquan Xiao, Jianguo Zhu
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    ABSTRACT: A giant d33 was attained in the 0.96(K0.46Na0.54+x)Nb0.95Sb0.05O3–0.04Bi0.5(Na0.82K0.18)0.5ZrO3 ceramic by doping nonstoichiometric sodium. A rhombohedral–tetragonal phase boundary is constructed in the ceramic with a wide Na+ nonstoichiometry. Enhanced piezoelectric activity (e.g. d33 ≈ 496 pC N−1 and kp ≈ 47%) was observed in the ceramics with a 0.5% excess of Na+. In addition, enhanced stability of ferroelectricity and piezoelectricity is also shown in this ceramic. We suggest that such a giant piezoelectricity might spark enthusiasm for research into potassium–sodium niobate ceramics.
    Scripta Materialia 01/2015; 94. DOI:10.1016/j.scriptamat.2014.09.008 · 2.97 Impact Factor
  • ACS Applied Materials & Interfaces 01/2015; · 5.90 Impact Factor
  • Jiagang Wu, Dingquan Xiao, Jianguo Zhu
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    ABSTRACT: Potassium-sodium niobate lead-free piezoceramics have received considerable attention for replacing lead-based ones in some practical applications. This review covers the fundamental aspects of potassium-sodium niobate lead-free piezoelectrics in terms of the relationships between new phase boundaries and high piezoelectric activity. The enhancement in its piezoelectric response is primarily concerned for piezoelectric devices. For a potassium-sodium niobate material, the phase boundaries modifications are important to achieve a high piezoelectric activity. In addition, the compositions concerning phase boundaries have a significant impact on the intensities of piezoelectric properties. Correct evaluation of piezoelectric properties is becoming more important in enabling an accurate comparison of a number of studies based on different systems. In the latter part, our recent advances in its piezoelectric properties are presented with a focus on potassium-sodium niobate to give an overview of the various problems and solutions.
    Journal of Materials Science Materials in Electronics 01/2015; DOI:10.1007/s10854-015-3084-2 · 1.97 Impact Factor
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    ABSTRACT: The obvious conflicts between large piezoelectricity and high strain could be solved by developing new phase boundaries in potassium–sodium niobate materials. Here, we have solved this problem by extensive experimental researches and induced a larger strain as well as a higher piezoelectricity in (K, Na)NbO3. Large converse piezoelectric coefficient (d*33 = 599–1553 pm V−1) and high strain (0.18–0.46%) were achieved, which are the highest values reported to date in potassium–sodium niobate, suggesting that such a system is a promising lead-free candidate for electromechanical actuator applications. In addition, high d33 values of 400–490 pC N−1 have also been attained in the ceramic due to its rhombohedral–tetragonal phase boundary, as well as its composition.
    12/2014; 3(5). DOI:10.1039/C4TA05423G
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    ABSTRACT: Mn-doped BiFeO3 (BFO) thin films with nominal composition of BiFe1−x Mnx O3 (x = 0.00, 0.01, 0.03, 0.05, 0.07) were deposited on (111)Pt/Ti/SiO2/Si substrates via a simple sol–gel spin-coating method with rapid thermal annealing process. The BFO films with different Mn dopant contents were well crystallized in the perovskite structure and their overlapped (110) diffraction peaks shifted toward higher angles with the increase in Mn content, indicating a slight distortion in the lattice structure. Improved microstructure with smaller grain size and diminished structural defects can be observed in the films of x around 0.03. X-ray photoelectron spectroscopy analysis confirmed the coexistence of 2+ and 3+ electronic states for Fe element and proper substitution of Mn for Fe can decrease the amount of Fe2+ while excess doping results in increasing Fe2+ content. The intrinsic ferroelectric polarization was hard to be measured in the pure BFO film due to high leakage contribution, whereas the x = 0.03, 0.05 and 0.07 films exhibited well-saturated rectangular shape-like ferroelectric hysteresis loops, and more importantly, perfectly closed hysteresis loops were obtained for the x = 0.03 film with a 2Pr value of 85.2 µC/cm2. The leakage current density in high electric field region was dramatically decreased by Mn doping, e.g. decreased to 3.3 × 10−4 A/cm2 at electric filed intensity of 170 kV/cm for the x = 0.03 film. Detailed leakage current characteristic analysis suggested that the dominant conduction mechanism in the pure BFO film was the space charge limited conduction at medium/high electric fields, which was associated with the space charges originated by oxygen vacancies; however, the leakage current of the x = 0.03 film was dominated by the Schottky mechanism in medium/high electric field region.
    Journal of Materials Science Materials in Electronics 12/2014; 26(3). DOI:10.1007/s10854-014-2598-3 · 1.97 Impact Factor
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    ABSTRACT: A high strain is important for practical applications of piezoelectric actuators. Here we reported a high strain in the (K,Na)NbO3 -based ceramics by doping alkaline earths or transition metals. The ceramics possess a high strain (∼0.29%) as well as a large converse piezoelectric coefficient (d33*) up to 688 pm/V, which almost matches that of PZT4 ceramics. The obtained d33* is high for nontextured (K,Na)NbO3-based ceramics. In addition, a higher d33 value (340-407 pC/N) was also attained in the ceramics. Enhanced d33 and d33* values of this work should be attributed to the multiphase coexistence's effect induced by alkaline earths or transition metals. We believe that our research can benefit the developments of (K,Na)NbO3 ceramics and widen their applications range.
    ACS Applied Materials & Interfaces 11/2014; DOI:10.1021/am505887y · 5.90 Impact Factor
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    ABSTRACT: The tightly coupled heterostructure g-C3N4/Au/poly(3-hexylthiophene) (P3HT)/Pt was successfully prepared by self-assembling method. The heterojunction photocatalyst displayed high activity for hydrogen production from water which contains triethanolamine as an electron donor under visible light irradiation. The samples were characterized by X-ray diffraction (XRD), UV-vis spectroscopy, photoluminescence (PL) spectra analysis and transmission electron microscopy (TEM), respectively. The experimental results demonstrated that the g-C3N4/Au/P3HT/Pt structure was conducive to the efficiently separation of photo-generated electron-hole pairs, which can be explained by the strong junction of chemical bond between Au and P3HT. The effect of P3HT content on the activity of the photocatalysts was investigated with a series of g-C3N4/Au/P3HT heterostructure samples loaded Pt as a cocatalyst in triethanolamine aqueous solutions. The optimal P3HT content was determined to be 0.5 wt%, and the corresponding hydrogen evolution rate was 320 mol h-1.
    11/2014; 3(1). DOI:10.1039/C4TA04636F
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    ABSTRACT: Aurivillius-type Bi4Ti3-xWx/2Nbx/2O12 ceramics were prepared by a conventional solid-state sintering method. The XRD patterns demonstrated that all compositions were a single three layered crystalline structure, involving a reduction of lattice distortion with an increase in W/Nb doping level. The electrical properties including dielectric, electrical conduction and piezoelectric properties were tailored by W/Nb additives. The Curie-temperature decreased, whereas the electrical resistivity drastically increased with introduction of W/Nb donor dopants. As a result, a high electric field can be applied during the poling process. The Bi4Ti2.9W0.05Nb0.05O12 ceramics exhibited optimum piezoelectric coefficient (d(33) similar to 22.8 pC/N), large remnant polarization (2P(r) similar to 26.8 mu C/cm(2) @ 200 degrees C) together with a high Curie temperature (T-c similar to 635 degrees C). Furthermore, this composition possessed a wide sintering window with outstanding piezoelectric properties. These parameters indicate that Bi4Ti2.9W0.05Nb0.05O12-based ceramic is a promising candidate for high temperature piezoelectric applications.
    Materials Research Bulletin 11/2014; 59:125–130. DOI:10.1016/j.materresbull.2014.07.002 · 1.97 Impact Factor
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    ABSTRACT: 0.95(K0.5Na0.5)NbO3–0.05(Bi0.5Na0.5)ZrO3–xZnO (KNN–BNZ–xZnO) lead-free piezoceramics were prepared by the conventional solid-state method, and effects of ZnO content on their phase structure, microstructure, and electrical properties were studied. The ceramics with x=0.01 possess the mixture of both rhombohedral–orthorhombic and orthorhombic–tetragonal phase boundaries. Their grain size becomes more homogenous and much smaller with the addition of ZnO. Enhanced dielectric and piezoelectric properties (e.g., d33=320 pC/N, kp=0.484, TC=320 °C) were observed in the ceramic with x=0.01. These results show that such a material system belongs to be a promising lead-free piezoelectric material.
    Ceramics International 11/2014; 40(9):14601–14605. DOI:10.1016/j.ceramint.2014.06.045 · 2.09 Impact Factor
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    ABSTRACT: The effect of Ce-substitution for A-site on the electrical properties of (NaBi)0.49[ ]0.02Bi2Nb1.98Ta0.02O9-based piezoceramics prepared by the conventional solid state sintering method was investigated. The dense microstructure with ~98% theoretical density was well developed in this material system, presenting a typical Aurivillius phase structure. The Curie temperature (TC) gradually decreases from 791 °C to 770 °C with increasing Ce3+ content. Moreover, doping with Ce3+ significantly increases the piezoelectric constant (d33) and decreases the coercive field. The (NaBi0.92Ce0.08)0.49[ ]0.02Bi2Nb1.98Ta0.02O9 ceramic exhibits optimum electrical properties (e.g., d33~24 pC/N, kp~8.4%, Qm~3488), together with a relatively high TC (~776 °C). These results indicate that this ceramic is a promising candidate for high-temperature piezoelectric applications.
    Ceramics International 11/2014; 40(9):14159-14163. DOI:10.1016/j.ceramint.2014.06.002 · 2.09 Impact Factor