本文選題：前鈣鈦礦 + 鈣鈦礦�。� 參考：《浙江大學(xué)》2015年碩士論文

【摘要】：由于具有鐵電性、壓電性、高溫超導(dǎo)特性、巨磁阻效應(yīng)等豐富的物理性能,鈣鈦礦結(jié)構(gòu)及其氧化物已廣泛應(yīng)用于或有望應(yīng)用于鐵電非揮發(fā)性存儲器(FeRAM)、傳感器、薄膜電容器、紅外探測器、納米發(fā)電機等。隨著電子器件的多功能化及小型化,作為許多元件中重要組成部分的鈣鈦礦結(jié)構(gòu)氧化物,其納米尺寸調(diào)控、性能優(yōu)化以及新材料的探索也日漸深入。本文首先綜述了鈣鈦礦相氧化物的結(jié)構(gòu)特點以及零維、一維和二維鈣鈦礦鐵電氧化物納米材料的性能及其尺寸效應(yīng)研究現(xiàn)狀；其次,對各類制備鈣鈦礦鐵電氧化物的方法進行了對比分析；最后,簡要介紹了鈣鈦礦結(jié)構(gòu)氧化物的介電性能、鐵電性能及反鐵電性能。基于以上研究現(xiàn)狀和發(fā)展趨勢,本文結(jié)合改性溶膠-凝膠法、水熱法和固態(tài)相變法,實現(xiàn)了前鈣鈦礦相(Pre-perovskite PbTiO3, PP-PT)及四方鈣鈦礦相鈦酸鉛(Perovskite PbTiO3, PT)納米纖維的尺寸可控制備；將長徑比高、分散性良好的PT納米纖維與聚偏氟乙烯(PVDF)昆合制備PVDF/PP-PT復(fù)合薄膜以及PVDF/PT復(fù)合薄膜；首次采用水熱法成功制備出鐵電體與反鐵電體復(fù)合的鈦酸鉛／鋯酸鉛(PT/PZ)復(fù)合纖維；利用高分辨透射電鏡(HRTEM)、掃描電鏡(SEM)、X射線衍射(XRD)、能量分散譜儀(EDS)等測試方法對所制備材料的晶體結(jié)構(gòu)、微結(jié)構(gòu)和元素分布進行了研究分析,揭示了調(diào)控機理及生長機制；采用多種分析測試技術(shù)對這些材料的介電性能、熒光性能等性能進行了研究。主要的研究成果如下：(1)結(jié)合改性溶膠-凝膠法和水熱法,通過調(diào)節(jié)三乙醇胺(TEA)與鈦酸四丁酯的比例實現(xiàn)了前鈣鈦礦相PT納米纖維的尺寸可控制備。TEA水溶液有效地調(diào)控了Ti前驅(qū)體的溶膠-凝膠過程,使得初始反應(yīng)物的分散性和均勻度都有極大的提高。進而在水熱反應(yīng)過程中,前鈣鈦礦相PT納米纖維的成核點數(shù)量增加,抑制了納米纖維的生長,最終合成了長度減小并且分散性良好的納米纖維。前鈣鈦礦相PT納米纖維的長度從35-90 μm減小到5-12μm,直徑始終保持在100-300 nm的范圍內(nèi),長徑比也從225-330降低到42-60。同時,前鈣鈦礦相PT納米纖維的分散性和直徑均勻度得到顯著提高。由于前鈣鈦礦相PT納米纖維的暴露面(110)晶面為Pb-O面,Pb／Ti比值能夠有效調(diào)控納米纖維的直徑。當(dāng)水熱反應(yīng)中Pb的含量不變時,納米纖維的直徑能夠保持在一定的范圍內(nèi)。不同尺寸前鈣鈦礦相PT納米纖維的熒光發(fā)光性能研究結(jié)果表明前鈣鈦礦相PT納米纖維在530-550nm處呈現(xiàn)出了寬的綠色發(fā)光峰,且無明顯尺寸效應(yīng)發(fā)生。(2)在水熱過程中,以PVA和PVP作為高分子表面修飾劑,獲得了長徑比約為100-200且分散性良好的單晶PP-PT納米纖維。在此基礎(chǔ)上制備了PVDF/PP-PT復(fù)合薄膜。在頻率范圍為5 kHz-300 kHz,隨著PP-PT納米纖維含量的增加,PVDF/PP-PT復(fù)合薄膜的介電常數(shù)也隨之增加。頻率為5 kHz時,樣品4(PP-PT納米纖維加入量為20%)的介電常數(shù)(εr=9.73)比樣品1(PP-PT納米纖維加入量為O%)的介電常數(shù)(εr=6.77)高43.7%。頻率高于300 kHz時,介電常數(shù)減小,介電損耗急劇增加,可能是由于PVDF以及PP-PT納米纖維中的偶極距轉(zhuǎn)向無法跟上電場的變化而發(fā)生了偶極子極化弛豫過程。同時,Cole-Cole圖分析結(jié)果表明隨著復(fù)合薄膜中PP-PT納米纖維含量的增加,弛豫時間從0.4067×10-7s增加到1.2830×10-7s。(3)以單晶四方鈣鈦礦相PT納米纖維為載體,與鋯酸鉛(PbZrO3, PZ)的前驅(qū)體進行水熱反應(yīng),首次成功合成了PT/PZ單晶異質(zhì)結(jié)復(fù)合纖維,長度約為15-65μm,直徑約為0.70-2.05μm。界面微結(jié)構(gòu)研究結(jié)果表明,單晶PT(011)晶面的晶格間距與單晶PZ(221)晶面的晶格間距相匹配,失配度為3.09%,存在外延生長的關(guān)系。PT納米纖維與PZ晶體界面處存在約10nm的Zr、Ti元素共存區(qū)域,且Zr元素己擴散進入至PT納米纖維內(nèi)部約20 nm處,預(yù)示著PT／PZ復(fù)合纖維中較大離子半徑的Zr4+離子取代了在PT納米纖維中較小離子半徑的Ti4+離子,從而使PT/PZ復(fù)合纖維中的PT納米纖維晶胞膨脹,四方性減弱。在此基礎(chǔ)上,提出擴散和外延生長機理來解釋復(fù)合纖維的生長。(4)在PT/PZ異質(zhì)結(jié)復(fù)合纖維的界面上,利用高溫退火處理的方式提供Zr4+離子和Ti4+離子的互擴散動力,合成出Pb(Zr0.44Ti0.56)O3(PZT)一維材料。
[Abstract]:Due to the rich physical properties of ferroelectric, piezoelectricity, high temperature superconductivity and giant magnetoresistance, perovskite structures and their oxides have been widely used or are expected to be applied to ferroelectric nonvolatile memory (FeRAM), sensors, film capacitors, infrared detectors, nanoscale generators and so on. With the multi-function and miniaturization of electronic devices, As an important part of the perovskite structure oxide in many components, its nano size regulation, performance optimization and new materials are becoming more and more in-depth. This paper first summarizes the structure characteristics and zero dimension of perovskite phase oxides, and studies the performance and size effect of one and two dimensional Perovskite Ferroelectric oxide nanomaterials. Secondly, the methods of preparing perovskite ferroelectric oxides are compared and analyzed. At last, the dielectric properties, ferroelectric properties and antiferroelectric properties of perovskite structure oxides are briefly introduced. Based on the above research status and development trend, this paper combines the modified sol gel method, the hydrothermal method and the solid-state phase transformation method to realize the pre calcium titanium. The size of Pre-perovskite PbTiO3 (PP-PT) and tetragonal perovskite phase lead titanate (Perovskite PbTiO3, PT) nanofibers can be controlled in size, and PVDF/PP-PT composite films and PVDF/PT composite films are prepared with high length diameter ratio, good dispersive PT nanofibers and poly vinylidene fluoride (PVDF). The first preparation of iron out by hydrothermal method is the preparation of iron out for the first time. The composite fiber of lead titanate / lead zirconate (PT/PZ) composite fiber and the antiferroelectrics are used to study the crystal structure, microstructure and distribution of the material by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X ray diffraction (XRD), and energy dispersive spectrometer (EDS). The mechanism and growth mechanism of the prepared materials are revealed. The dielectric properties and fluorescence properties of these materials were studied by a variety of analysis and testing techniques. The main research results were as follows: (1) the size of.TEA water in the pre perovskite phase PT nanofibers can be controlled by adjusting the proportion of TEA and four butyl titanate with the modified sol-gel method and the hydrothermal method. The sol-gel process of Ti precursor was effectively controlled by the solution, and the dispersion and uniformity of the initial reactants were greatly improved. In the process of hydrothermal reaction, the number of nucleation points of the preperovskite PT nanofibers increased and the growth of nanofibers was inhibited. Finally, the nanofibers with reduced length and good dispersibility were synthesized. Fiber. The length of PT nanofibers in the pre perovskite phase decreases from 35-90 to 5-12 m, the diameter is kept in the range of 100-300 nm, the length to diameter ratio is also reduced from 225-330 to 42-60.. The dispersion and diameter uniformity of the pre perovskite PT nanofibers are significantly improved. Due to the riot surface (110) surface (110) of the pre perovskite phase PT nanofibers The diameter of nanofibers can be effectively regulated by the ratio of Pb / Ti to the Pb-O surface. When the content of Pb is constant in the hydrothermal reaction, the diameter of the nanofibers can be kept in a certain range. The fluorescence luminescence properties of the perovskite PT nanofibers before different sizes show that the pre perovskite PT nanofibers are wide in the 530-550nm width. The green luminescence peak has no obvious size effect. (2) in the hydrothermal process, PVA and PVP are used as polymer surface modifiers to obtain the single crystal PP-PT nanofibers with a long diameter ratio of about 100-200 and good dispersion. On this basis, the PVDF/PP-PT composite thin films are prepared. The frequency range is 5 kHz-300 kHz, with the content of PP-PT nanofibers. The dielectric constant of PVDF/PP-PT composite film increases. When the frequency is 5 kHz, the dielectric constant (epsilon r=9.73) of sample 4 (PP-PT nanofiber adding 20%) is higher than that of sample 1 (PP-PT nanofiber O%) with high 43.7%. frequency higher than 300 kHz, and dielectric constant decreases and dielectric loss increases dramatically. The dipole polarization relaxation process has occurred because the dipole distance in PVDF and PP-PT nanofibers can not keep up with the change of the electric field. At the same time, the Cole-Cole diagram analysis shows that the relaxation time increases from 0.4067 x 10-7s to 1.2830 x 10-7s. (3) with the increase of the PP-PT nanofiber content in the composite film, and the single crystal tetragonal perovskite phase PT Nanofibers are used to react with the precursor of lead zirconate (PbZrO3, PZ). The PT/PZ single crystal heterojunction composite fiber is successfully synthesized for the first time. The length is about 15-65 u m and the diameter is about 0.70-2.05 mu m. interface microstructures. The results show that the lattice spacing of the single crystal PT (011) crystal is matched with the lattice spacing of the single crystal PZ (221) crystal surface. The degree is 3.09%, the relationship between the epitaxial growth and the relationship between.PT nanofibers and PZ crystals exists about 10nm Zr, the Ti element coexists in the region, and the Zr element has spread to about 20 nm within the PT nanofibers, indicating that the Zr4+ ion of the larger ionic radius in the PT / PZ composite fiber has replaced the smaller ion radius in the PT nanofibers. On this basis, the diffusion and epitaxial growth mechanism is proposed to explain the growth of the composite fibers. (4) the interaction between Zr4+ ions and Ti4+ ions is provided by high temperature annealing at the interface of PT/PZ heterojunction composite fibers, and Pb (Zr0.44) is synthesized. Ti0.56) O3 (PZT) one dimensional material.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ343;TB33

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本文編號：2083833