含銦之新穎熱電材料的合成與分析

Abstract

熱電材料（thermoelectric materials）是一種能將電能與熱能交互轉換的材料。目前熱電材料發展的挑戰在於提高能量轉換效能與熱穩定性，並降低材料成本。一個好的熱電材料需要具備高熱電力，良好的導電性及低導熱性，綜合各項因素，半導體材料為較具潛力之熱電材料，本論文以銦為主體合成新穎熱電材料並輔以理論計算來研究其性質。 經由理論計算得知AInX2與AIn5X8系統（A=Cu、Ag、Au，X= S、 Se、Te）因具有半導體性質，可能適合作為熱電材料。以此系列合成之產物經由X光繞射方法分析其結構，並期望以理論計算瞭解電子結構來推測改進材料性質之方法。最後經由物性測量來驗證理論計算之結果。 經由AuIn5Te8合成比例，目前於Au-In-Te系統中發現一新結構化合物，經過單晶繞射解析得其結構為Orthorhombic，晶格係數a=6.167(5) Å，b=12.34(1) Å，c=12.355(9) Å，V=940.156(6) Å3。元素分析結果為Au：In：Te=1：5.39：9.30詳細的晶體結構解析仍在進行中。

Thermoelectric(TE) materials can convert thermal energy from a temperature gradient into electrical energy (the Seebeck effect) or in the reverse process (the Peltier effect). The major challenge for good thermoelectric materials is to increase energy transfer efficiency, thermal stability and material cost. Good thermoelectric material should have high figure of merit, ZT=Sσ2/κ, that include high thermopower(S), high electrical conductivity(σ), and low thermal conductivity(κ). By combining these factors, the semiconductor material could be a potentially good thermoelectric material. This thesis is focus on the synthesis, characterization, and theoretical studies of indium related materials. According to the result of theoretical calculations, the AInX2 and AIn5X8 system (A = Cu, Ag, Au; X = S, Se, Te) may exhibit semiconducting property that could be used as thermoelectric material. The structure of these products were studied by X-ray diffraction. We hope to improve the thermoelectric property by theoretical calculations to understanding the electronic structures of these compounds. The theoretical calculated results of these products were verified via physical property measurements. A new compound in Au-In-Te system was synthesized by reaction of “AuIn5Te8”. The compound crystallizes in the orthorhombic system with a = 6.167(5) Å, b = 12.34(1) Å, c = 12.355(9) Å, V = 766.4(3) Å3. Elemental analyses show composition of Au：In：Te=1：5.39：9.30. The further research of this “AuIn5Te8” compound system is in progress.