本文選題：Zintl相 + 晶體結(jié)構(gòu)��； 參考：《山東大學(xué)》2017年博士論文

【摘要】：磷族Zintl相化合物數(shù)目眾多,憑借其復(fù)雜多樣的晶體結(jié)構(gòu)和組分構(gòu)成,在很多領(lǐng)域都表現(xiàn)出應(yīng)用潛力,例如鋰電、超導(dǎo)、巨磁阻和熱電等。隨著Zintl相化合物的種類日益豐富,其新穎的物理化學(xué)性質(zhì)使之作為新型功能材料的潛力備增。本文通過金屬助溶劑法和高溫固相法合成了一系列磷族Zintl相化合物,并對其晶體結(jié)構(gòu)、電子結(jié)構(gòu)、磁性和熱電性質(zhì)進行了研究。研究內(nèi)容和主要結(jié)果包括:(1)Sr14MgSb11和Eu14MgSb11的結(jié)構(gòu)、磁性和熱電性質(zhì)用固相方法在1323 K合成了兩個含Mg的銻基Zintl相化合物:Sr14MgSb11和Eu14MgSb11。兩個化合物是Ca14AlSb11結(jié)構(gòu)的衍生物,屬于四方晶系、I41/acd空間群。Sr14MgSb11的單胞參數(shù) a/c 是 17.5691(14)A/23.399(4)A,Eu14MgSb11 的單胞參數(shù)a/c是17.3442(11)A/22.981(3)A。電阻率與溫度的關(guān)系表明,Sr14MgSb11屬于本征半導(dǎo)體,而Eu14MgSb11屬于半金屬化合物。憑借低的熱導(dǎo)率和適中的Seebeck系數(shù),Sr14MgSb11和Eu14MgSb11具有作為熱電材料的潛力。磁性測試表明,Eu14MgSb11是反鐵磁性化合物,外斯溫度θ為-9.49 K。電子結(jié)構(gòu)計算顯示,Sr14MgSb11的帶隙為1.18 eV。(2)A14MgBi11(A=Ca,Sr,Eu,Yb)的結(jié)構(gòu)、磁性和熱電性質(zhì)用固相法合成了三個Bi基14-1-11化合物A14MgBi11(A=Ca,Sr,Eu),它們都屬于四方晶系、I41/acd(No.142)空間群。Ca14MgBi11、Sr14MgBi11和 Eu14MgBi11的晶胞參數(shù) a/c 分別是 17.0470(17)/22.665(5)A,17.854(2)/23.580(6)A 和17.6660(7)/23.2446(18)A。1000 Oe場強下的磁性測試表明,Eu14MgBi11是反鐵磁性化合物。電子結(jié)構(gòu)計算結(jié)果顯示,Ca14MgBi11是一個帶隙為1.12eV的p型半導(dǎo)體。由于復(fù)雜的結(jié)構(gòu)和較大的分子質(zhì)量,A14MgBi11(A=Ca,Sr,Eu,Yb)具有低的熱導(dǎo)率,ZT值在1073 K時分別達到0.21,0.71,0.46和0.55。隨著該系列化合物的發(fā)現(xiàn),14-1-11熱電材料的研究范圍也從Sb基化合物拓展到Bi基化合物,并且Bi化合物是一類很有前景的熱電功能材料。(3)Sr14MgAs11和Eu14MgAs11的結(jié)構(gòu)、磁性和光學(xué)性質(zhì)用高溫固相法合成了兩個Zint1相化合物:Sr14MgAs11和Eu14MgAs11,這是首次報道As基含Mg的14-1-11化合物。Sr14MgAs11的單胞參數(shù)為a=16.581 A,c=22.052 A;Eu14MgAs11的單胞參數(shù)為 a=16.3046 A,c=21.857 A。兩個化合物都屬于四方晶系,I41/acd(No.142,Z 8)空間群。Sr14MgAs11中As4原子存在占據(jù)率為16.3%的無序,As含量的減少導(dǎo)致精修后的分子式為Sr14MgAs10.33。熱分析表明,Eu14MgAs11在300K-973 K范圍內(nèi)是穩(wěn)定的。磁性測試表明,當(dāng)溫度為7.2 K時Eu14MgAs11發(fā)生反鐵磁性轉(zhuǎn)變。光學(xué)吸收測試顯示,Sr14MgAs11和Eu14MgAs11都是間接吸收半導(dǎo)體,帶隙分別是2.05 eV和1.92 eV。使用Wien2K軟件計算了態(tài)密度,結(jié)果顯示Sr14MgAs11是p型半導(dǎo)體。Sr14MgAs11和Eu14MgAs11的電學(xué)和熱學(xué)性質(zhì)需要進一步研究,憑借良好的熱穩(wěn)定性和復(fù)雜的晶體結(jié)構(gòu),兩個化合物有可能具有熱電材料應(yīng)用潛力。(4)Sr9Mg4.56Sb9的合成與晶體結(jié)構(gòu)使用金屬助溶劑法合成了新化合物Sr9Mg4.56Sb9,這是第一個被報道的含Mg的9-4-9化合物。Sr9Mg4.56Sb9屬于正交晶系、Pnna(No.62,Z=4)空間群。單胞參數(shù) a=13.0962(11)A,b=4.8193(4)A,c=46.259(4)A。陰離子框架是由[MgSb4]四面體與[MgSb3]平面三角形共邊或者共頂點連接形成的鏈條,陽離子Sr2+分布在鏈與鏈的中間。Mg和Sb的多個位置都存在無序現(xiàn)象,憑借高密度點缺陷和復(fù)雜結(jié)構(gòu),Sr9Mg4.56Sb9可能有低的熱導(dǎo)率和良好的熱電性能。(5)Sr11Mg4As10的晶體結(jié)構(gòu)和電子結(jié)構(gòu)用金屬Sn做助溶劑,合成了一個全新比例的Zint1相化合物Sr11Mg4As10)。該化合物屬于正交晶系、Pnnm(No.58)空間群。晶胞參數(shù)a=14.542(6)A,b=22.018(10)A,c=4.4981(19)A。陰離子部分是由[MgAs4]四面體共頂點連接組成的一維鏈,Sr2+作為陽離子分布鏈中間。計算電子結(jié)構(gòu)表明,Sr11Mg4As10屬于半導(dǎo)體。(6)Ca2Si的熱電性質(zhì)使用電磁感應(yīng)熔煉爐制備了 Ca2Si多晶樣品,對其電學(xué)和熱學(xué)性質(zhì)進行了研究,這是該化合物的熱電性能第一次被報道。電阻率隨溫度上升一直緩慢升高,顯示出了強烈的金屬性。雖然Ca2Si有較低的熱導(dǎo)率(約1 W/m·K),但是由于其較低的Seebeck系數(shù),最大ZT值在873 K只達到0.1左右。通過Si/Sn互摻,制備了 Ca2Si1-xSnx(0x1)系列化合物,這有可能調(diào)節(jié)載流子濃度,提高材料的熱電性能。
[Abstract]:A large number of Zintl phase compounds have shown potential applications in many fields, such as lithium, superconductivity, giant magnetoresistance and thermoelectricity in many fields. With the increasing variety of Zintl phase compounds, their novel physical and chemical properties make it potential as a new functional material. A series of phosphorous Zintl phase compounds were synthesized by metal cosolvent method and high temperature solid state method, and their crystal structure, electronic structure, magnetic properties and thermoelectric properties were studied. The contents and main results include: (1) the structure of Sr14MgSb11 and Eu14MgSb11, magnetic and thermoelectric properties, two Mg containing antimony were synthesized by solid method in 1323 K Base Zintl phase compounds: two compounds of Sr14MgSb11 and Eu14MgSb11. are derivatives of Ca14AlSb11 structure and belong to the tetragonal system. The single cell parameter a/c of I41/acd space group.Sr14MgSb11 is 17.5691 (14) A/23.399 (4) A, and the a/c cell parameter of Eu14MgSb11 is 17.3442 (11) A/22.981 (3) and the relation between resistivity and temperature. Semiconductors, and Eu14MgSb11 belong to semi metal compounds. With low thermal conductivity and moderate Seebeck coefficients, Sr14MgSb11 and Eu14MgSb11 have potential as thermoelectric materials. Magnetic tests show that Eu14MgSb11 is antiferromagnetic, and the outer temperature theta is a -9.49 K. electronic structure, and the band gap of Sr14MgSb11 is 1.18 eV. (2) A14MgBi11 (2). The structure, magnetic and thermoelectric properties of A=Ca, Sr, Eu, Yb) are composed of three Bi based 14-1-11 compounds, A14MgBi11 (A=Ca, Sr, Eu), all of which belong to the tetragonal system, I41/acd (No.142) space group, respectively, 17.0470 (17) (5), 17.854 (2) 6 (6) and 17.6660 (7) (7). 18) the magnetic test under the A.1000 Oe field strength shows that Eu14MgBi11 is an antiferromagnetic compound. The results of the electronic structure calculation show that Ca14MgBi11 is a p type semiconductor with a gap of 1.12eV. Due to the complex structure and large molecular mass, the A14MgBi11 (A=Ca, Sr, Eu, Yb) has a low thermal conductivity, and the ZT values are reached and 0 respectively at the time of 1073. .55. with the discovery of this series of compounds, the research scope of 14-1-11 thermoelectric materials is also extended from Sb based compounds to Bi based compounds, and Bi compounds are a very promising thermal functional material. (3) the structure of Sr14MgAs11 and Eu14MgAs11, magnetic and optical properties have been synthesized by high temperature solid phase method for two Zint1 phase compounds: Sr14MgAs11 and Eu. 14MgAs11, this is the first report that the single cell parameter of the 14-1-11 compound containing the Mg of the As based.Sr14MgAs11 is a=16.581 A, c=22.052 A, and the single cell parameter of Eu14MgAs11 is a=16.3046 A, and the two compounds are all Quartet systems. Sr14MgAs10.33. thermal analysis of the molecular formula after refinement indicates that Eu14MgAs11 is stable within the range of 300K-973 K. The magnetic test shows that when the temperature is 7.2 K, Eu14MgAs11 has an antiferromagnetic transition. The optical absorption test shows that both Sr14MgAs11 and Eu14MgAs11 are indirect absorption semi conductors, and the band gap is 2.05 eV and 1.92 eV. uses Wien2. The K software calculates the density of States, the results show that Sr14MgAs11 is p type semiconductor.Sr14MgAs11 and Eu14MgAs11, the electrical and thermal properties need further study. With good thermal stability and complex crystal structure, the two compounds may have potential for application of thermoelectric materials. (4) the synthesis of Sr9Mg4.56Sb9 and the use of metal solubilization for crystal structure A new compound, Sr9Mg4.56Sb9, is synthesized by the agent method. This is the first reported 9-4-9 compound containing Mg,.Sr9Mg4.56Sb9 belongs to the orthogonal crystal system, Pnna (No.62, Z=4) space group. The single cell parameter a=13.0962 (11) A, b=4.8193 (4) A, c=46.259 (4) is formed by the tetrahedron with the common vertex or common vertex connection of the tetrahedron. Chain, the distribution of cationic Sr2+ in the middle of chain and chain of.Mg and Sb, there are many disordered phenomena. With high density point defect and complex structure, Sr9Mg4.56Sb9 may have low thermal conductivity and good thermoelectric properties. (5) the crystal structure and electronic structure of Sr11Mg4As10 are used as Sn as a cosolvent, and a new proportion of Zint1 phase is synthesized. Compound Sr11Mg4As10). The compound belongs to the orthogonal crystal system, the Pnnm (No.58) space group. The cell parameter a=14.542 (6) A, b=22.018 (10) A, c=4.4981 (19) A. anion part is a one-dimensional chain composed of the common vertex connection of the [MgAs4] tetrahedron, Sr2+ as a cationic distribution chain. The electronic structure shows that Sr11Mg4As10 belongs to the semiconductor. (6) heat of heat. Ca2Si polycrystalline samples were prepared by electromagnetically induced melting furnace, and their electrical and thermal properties were studied. This is the first time that the thermoelectric properties of the compound have been reported. The resistivity increases slowly with the increase of temperature, showing a strong metallic property. Although Ca2Si has a lower thermal conductivity (about 1 W/m. K), it is compared to the result of its relatively low thermal conductivity. The low Seebeck coefficient and the maximum ZT value are only about 0.1 at 873 K. A series of Ca2Si1-xSnx (0x1) compounds are prepared through the blending of Si/Sn, which may regulate the carrier concentration and improve the thermoelectric properties of the material.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TB34

【相似文獻】

相關(guān)期刊論文 前3條

1 賈永忠;景燕;馬軍;岳都元;Claude Belin;Monique Tillard;;鹽湖豐產(chǎn)元素與Zintl化合物(續(xù)完)[J];鹽湖研究;2011年02期

2 賈永忠;景燕;馬軍;岳都元;Claude Belin;Monique Tillard;;鹽湖豐產(chǎn)元素與Zintl化合物[J];鹽湖研究;2010年04期

3 ;[J];;年期

相關(guān)會議論文 前1條

1 王建;夏盛清;陶緒堂;;磷族Zintl相半導(dǎo)體化合物的合成,結(jié)構(gòu)與性質(zhì)[A];中國化學(xué)會第28屆學(xué)術(shù)年會第8分會場摘要集[C];2012年

相關(guān)博士學(xué)位論文 前2條

1 劉小村;新穎Zintl相砷化物的合成、結(jié)構(gòu)與性質(zhì)[D];山東大學(xué);2015年

2 譚文杰;磷族Zintl相新化合物的合成探索與性質(zhì)[D];山東大學(xué);2017年

相關(guān)碩士學(xué)位論文 前1條

1 張榮;含過渡金屬的Zintl相砷化物的合成、結(jié)構(gòu)、性質(zhì)及理論研究[D];山東大學(xué);2016年

，

本文編號：1969815