鈣鈦礦結(jié)構(gòu)Pb、Te氧化物的合成與物性研究
發(fā)布時間：2018-08-21 13:20
【摘要】：鈣鈦礦氧化物具有優(yōu)異的物理及化學(xué)性能,如鐵電性、鐵磁性、壓電性等,成為現(xiàn)代材料領(lǐng)域的研究熱點。另外,由于含Pb或者含Te原子的鈣鈦礦化合物中會產(chǎn)生結(jié)構(gòu)畸變出現(xiàn)新的性能而被學(xué)者廣泛研究,因此本文對鈣鈦礦結(jié)構(gòu)的Pb、Te氧化物的合成與物性展開了探索性研究。本論文的工作主要包括三部分,第一部分采用熔融法合成出四方相、斜方相和立方相的PbTeO3,并對合成的樣品進(jìn)行物相分析,未得到純相的樣品;第二部分利用水熱合成法制備出四方相PbTeO3單晶樣品,對四方相PbTeO3單晶樣品進(jìn)行粉末X射線衍射、紅外吸收光譜、常壓拉曼光譜和高壓拉曼光譜測量分析后得到以下結(jié)論:(1)四方相PbTe03的紅外吸收光譜測量顯示四個吸收峰分別位于634 cm-1、649 cm-1、670 cm-1和734 cm-1的位置,其中600 cm-1至700 cm-1處的吸收峰歸屬于Te-0鍵的伸縮振動。(2)結(jié)合理論計算的結(jié)果發(fā)現(xiàn)實驗測量得到的常壓拉曼譜中,位于600 cm-1至800 cm-1波數(shù)段的拉曼峰歸屬于Te032-酸根中Te-0鍵的對稱伸縮振動模和反對稱伸縮振動;位于178 cm-1至400 cm-1波數(shù)段的拉曼峰歸屬于TeO32-酸根整體的旋轉(zhuǎn)、彎曲、搖擺等外振動模;而波數(shù)值小于144 cm-1的拉曼峰是由晶格振動模和Te032-酸根剛性多面體單元的外振動模共同引起的。(3)高壓原位測量拉曼光譜研究發(fā)現(xiàn),隨著腔體壓力增大至13.4 GPa時,四方相PbTe03的拉曼光譜在119 cm-1位置處的拉曼峰劈裂成兩個拉曼峰,這可能是由TeO32-酸根剛性多面體的旋轉(zhuǎn)所致,并不是PbTe03在壓力的作用下發(fā)生相變;當(dāng)壓力升至18 GPa時,整個拉曼譜的拉曼峰出現(xiàn)峰形變寬,強(qiáng)度減弱的情況,說明此時拉曼振動模開始出現(xiàn)軟化,四方相PbTe03的晶體結(jié)構(gòu)開始出現(xiàn)不穩(wěn)定的情形。第三部分采用水熱合成法制備出純相的正交結(jié)構(gòu)的Pb2Te308晶體,對正交相的Pb2Te3O8進(jìn)行紅外吸收光譜、紫外可見吸收光譜以及拉曼光譜測量分析發(fā)現(xiàn):(1)Pb2Te3O8 的紅外吸收峰位置分別位于 404 cm-1、578 cm-1、658 cm-1、694 cm-1、739 cm-1位置處;(2)由Pb2Te3O8的紫外吸收光譜計算出了 Pb2Te3O8是帶隙寬度為3.57ev的絕緣體;(3)正交相Pb2Te3O8單晶的常壓拉曼光譜圖,根據(jù)相關(guān)研究我們推測在Pb2Te3O8中,600 cm-1-800 cm-1波數(shù)范圍內(nèi)的 637 cm-1、657 cm-1、689 cm-1、723 cm-1、736 cm-1和761 cm-1六個拉曼峰是屬于內(nèi)部伸縮振動模,50 cm-1-400 cm-1頻率范圍的振動對應(yīng)于晶格振動模式和Te3O84+基團(tuán)的外振動模式;(4)高壓原位測量拉曼光譜顯示正交相的Pb2Te3O8晶體結(jié)構(gòu)可穩(wěn)定的保持至腔體壓力達(dá)到21.8 GPa而不發(fā)生相變。
[Abstract]:Perovskite oxides with excellent physical and chemical properties, such as ferroelectricity, ferromagnetism, piezoelectric properties and so on, have become the research hotspot in the field of modern materials. In addition, due to the new properties of perovskite compounds containing Pb or Te atoms, the synthesis and physical properties of perovskite-based PbTE-Te oxides have been investigated. In the first part, tetragonal phase, oblique phase and cubic phase PbTeO _ 3 were synthesized by melting method. In the second part, tetragonal PbTeO3 single crystal samples were prepared by hydrothermal synthesis. The tetragonal PbTeO3 single crystal samples were characterized by powder X-ray diffraction and infrared absorption spectra. The results of atmospheric Raman spectroscopy and high pressure Raman spectroscopy are as follows: (1) the infrared absorption spectra of tetragonal PbTe03 show that the four peaks are located at 634 cm-1649 cm-1670 cm-1 and 734 cm-1, respectively. The absorption peaks from 600 cm-1 to 700 cm-1 belong to the stretching vibration of the Te-0 bond. (2) in combination with the theoretical results, it is found that the Raman spectra at atmospheric pressure are obtained from the experimental measurements. The Raman peaks located between 600 cm-1 and 800 cm-1 belong to the symmetric stretching mode and antisymmetric stretching mode of Te-0 bond in Te032- acid group, and the Raman peak from 178 cm-1 to 400 cm-1 belongs to the rotational, bending and swaying modes of TeO32- acid group. The Raman peak with wave value less than 144 cm-1 is caused by both the lattice vibration mode and the external vibration mode of the Te032-acid rigid polyhedron element. (3) the Raman spectra of high pressure in-situ measurements show that with the increase of cavity pressure to 13.4 GPa, The Raman spectra of tetragonal PbTe03 split into two Raman peaks at the position of 119 cm-1, which may be due to the rotation of the rigid polyhedron of TeO32-, not the phase transition of PbTe03 under pressure, when the pressure rises to 18 GPa. The Raman peak of the whole Raman spectrum is characterized by wide deformation and weak intensity, which indicates that the Raman vibration mode begins to soften and the crystal structure of tetragonal PbTe03 begins to be unstable. In the third part, pure phase Pb2Te308 crystal with orthogonal structure was prepared by hydrothermal synthesis method. Infrared absorption spectra of Pb2Te3O8 were obtained. The results of UV-Vis absorption spectra and Raman spectra show that: (1) the infrared absorption peak of Pb2Te3O8 is located at the position of 404 cm-1578 cm-1658 cm-1694 cm-1739 cm-1, and (2) from the UV absorption spectra of Pb2Te3O8, it is calculated that Pb2Te3O8 is an insulator with band gap width of 3.57ev. (3) the atmospheric pressure Raman spectra of orthotropic Pb2Te3O8 single crystals, Based on the relevant studies, we speculate that the six Raman peaks of 637 cm-1657 cm-1689 cm-1723 cm-1736 cm-1 and 761 cm-1 in the Pb2Te3O8 range of 600 cm-1-800 cm-1 are corresponding to the lattice vibration mode and Te3O84 group in the frequency range of 50 cm-1-400 cm-1. (4) the high pressure in-situ measurements show that the Pb2Te3O8 crystal structure can be kept stable until the cavity pressure reaches 21.8 GPa without phase transition.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O611.62
本文編號：2195864
[Abstract]:Perovskite oxides with excellent physical and chemical properties, such as ferroelectricity, ferromagnetism, piezoelectric properties and so on, have become the research hotspot in the field of modern materials. In addition, due to the new properties of perovskite compounds containing Pb or Te atoms, the synthesis and physical properties of perovskite-based PbTE-Te oxides have been investigated. In the first part, tetragonal phase, oblique phase and cubic phase PbTeO _ 3 were synthesized by melting method. In the second part, tetragonal PbTeO3 single crystal samples were prepared by hydrothermal synthesis. The tetragonal PbTeO3 single crystal samples were characterized by powder X-ray diffraction and infrared absorption spectra. The results of atmospheric Raman spectroscopy and high pressure Raman spectroscopy are as follows: (1) the infrared absorption spectra of tetragonal PbTe03 show that the four peaks are located at 634 cm-1649 cm-1670 cm-1 and 734 cm-1, respectively. The absorption peaks from 600 cm-1 to 700 cm-1 belong to the stretching vibration of the Te-0 bond. (2) in combination with the theoretical results, it is found that the Raman spectra at atmospheric pressure are obtained from the experimental measurements. The Raman peaks located between 600 cm-1 and 800 cm-1 belong to the symmetric stretching mode and antisymmetric stretching mode of Te-0 bond in Te032- acid group, and the Raman peak from 178 cm-1 to 400 cm-1 belongs to the rotational, bending and swaying modes of TeO32- acid group. The Raman peak with wave value less than 144 cm-1 is caused by both the lattice vibration mode and the external vibration mode of the Te032-acid rigid polyhedron element. (3) the Raman spectra of high pressure in-situ measurements show that with the increase of cavity pressure to 13.4 GPa, The Raman spectra of tetragonal PbTe03 split into two Raman peaks at the position of 119 cm-1, which may be due to the rotation of the rigid polyhedron of TeO32-, not the phase transition of PbTe03 under pressure, when the pressure rises to 18 GPa. The Raman peak of the whole Raman spectrum is characterized by wide deformation and weak intensity, which indicates that the Raman vibration mode begins to soften and the crystal structure of tetragonal PbTe03 begins to be unstable. In the third part, pure phase Pb2Te308 crystal with orthogonal structure was prepared by hydrothermal synthesis method. Infrared absorption spectra of Pb2Te3O8 were obtained. The results of UV-Vis absorption spectra and Raman spectra show that: (1) the infrared absorption peak of Pb2Te3O8 is located at the position of 404 cm-1578 cm-1658 cm-1694 cm-1739 cm-1, and (2) from the UV absorption spectra of Pb2Te3O8, it is calculated that Pb2Te3O8 is an insulator with band gap width of 3.57ev. (3) the atmospheric pressure Raman spectra of orthotropic Pb2Te3O8 single crystals, Based on the relevant studies, we speculate that the six Raman peaks of 637 cm-1657 cm-1689 cm-1723 cm-1736 cm-1 and 761 cm-1 in the Pb2Te3O8 range of 600 cm-1-800 cm-1 are corresponding to the lattice vibration mode and Te3O84 group in the frequency range of 50 cm-1-400 cm-1. (4) the high pressure in-situ measurements show that the Pb2Te3O8 crystal structure can be kept stable until the cavity pressure reaches 21.8 GPa without phase transition.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O611.62
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 李大光;章弘毅;張鶴豐;郭清泉;曹明澈;;鈣鈦礦型復(fù)合氧化物的研究與應(yīng)用進(jìn)展[J];材料導(dǎo)報;2006年S1期
2 牛新書;曹志民;;鈣鈦礦型復(fù)合氧化物光催化研究進(jìn)展[J];化學(xué)研究與應(yīng)用;2006年07期
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