利用化學還原法快速合成近分散之Marcasite CuSe_2與Berzelianite Cu_2Se晶體及特性之研究

Rapid Synthesis of Nearly Dispersed Marcasite CuSe_2 and Berzelianite Cu_2Se Crystallites Using Chemical Reduction Processes

楊長庭(C.T. Yang) ； 向性一(H.I Hsiang) ； 孫曼庭(M.T. Sun) ； 吳羽千(Y.C. Wu)

《鑛冶：中國鑛冶工程學會會刊》 61卷1期 (2017/03) Pp. 81-88

https://doi.org/10.30069/MM.201703_61(1).0008

摘要

本研究利用新穎之製程搭配不同溶劑系統三乙二醇(triethylene glycol；TEG)、三乙烯四胺(triethylenetetramine；TETA)及包覆劑(polyvinylpyrrolidone；PVP)，成功製備出近分散之m-CuSe_2與b-Cu_2Se之晶體。利用X光繞射儀(XRD)、掃描式電子顯微鏡(SEM)、穿透式電子顯微鏡(TEM)、X光光電子能譜儀(XPS)及紫外-可見-近紅外光分光光譜儀(UV-Vis-NIR)分析晶體之結晶相、粒徑大小及型態、電子價數及能隙值。實驗結果顯示當TETA添加量為低濃度時，Cu離子始終維持Cu^(2+)，元素Se則還原至Se_2^(2-)離子，因此主要獲得之結晶相為m-CuSe_2與krutaite CuSe_2。進一步提升TETA濃度至0.147M後，因溶液中之還原性極劇增強，Cu^(2+)離子會還原至Cu^+，Se_2^(2-)離子會還原成Se^(2-)，因此可抑制中間產物Cu_3Se_2、Cu_(2-x)Se晶體的生成，而獲得單一結晶相之b-Cu_2Se晶體。此外，將krutaite CuSe_2於空氣氣氛300℃持溫30分鍾熱處理後，發現krutaite CuSe_2會相轉變為具有超導特性之單一結晶相m-CuSe_2。經UV-Vis-NIR分析可得m-CuSe_2之能隙值為1.49 eV，b-Cu_2Se之能隙值為1.98 eV。

關鍵字

m-CuSe_2 ； b-Cu_2Se ； 三乙烯四胺 ； 超導相轉換 ； 化學還原法

並列摘要

Nearly dispersed marcasite CuSe_2 (m-CuSe_2) and berzelianite Cu_2Se (b-CuSe_2) crystals were successfully prepared by thermal decomposition of copper and selenium-triethylene glycol (TEG) solution using triethylenetetramine (TETA) as the reducing agent and polyvinylpyrrolidone (PVP) as the capping agent. The crystalline structure, electronic, and copper selenide particle optical characterization were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible absorbance spectra. The TETA additive effects on crystal phase development and morphology were investigated. When TETA additive concentration was 0.007 M, the synthesized copper selenides were m-CuSe_2 and b-CuSe_2. When TETA additive concentration was 0.147 M, the synthesized copper selenides were mainly b-CuSe_2. The measured energy gaps for m-CuSe_2 and b-CuSe_2 were 1.49 eV and 1.98 eV, respectively. The marcasite CuSe_2 was obtained by annealing krutaite CuSe_2 at 300 ℃ for 30 minutes.

並列關鍵字

m-CuSe_2 ； b-Cu_2Se ； TETA ； superconducting phase transformation ； chemical synthesis process