A new insight into the thermodynamical criterion for the preparation of semiconductor and metal nanocrystals using a polymerized complexing method.
A new insight into the thermodynamical criterion for the preparation of semiconductor and metal nanocrystals using a polymerized complexing method.
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DOI：
10.1039/c7cp04097k
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
Pingyun Li;Qingqing Wang;Guodong Deng;Xiaode Guo;Wei Jiang;Hongying Liu;Feng-sheng Li;N. Thanh
中科院分区：
文献类型：
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作者：
Pingyun Li;Qingqing Wang;Guodong Deng;Xiaode Guo;Wei Jiang;Hongying Liu;Feng-sheng Li;N. Thanh
本文报道了聚合络合法制备金属和半导体纳米晶的本征化学判据。该方法的基本原理是通过蒸发溶剂在水溶液或乙二醇溶液中形成一元、二元或三元金属离子与键合剂之间的聚合络合结构。在N2气氛下热处理络合结构产生H2和CH 4气体，其可以将氧化物晶核还原为半导体和金属纳米晶体。实验结果表明，该方法可以制备出Te、CdTe、Ag 2 Te、CuTe、NiTe1.5、CoTe1.5、Bi 2 Te 3、Sb 2 Te 3、Bi-Sb、In 2 Te 3、Ni2.9SnTe2、CuGaTe 2、CuInS 2等半导体和Bi、Sb、Ag、Cu、Ni等金属纳米晶。透射电子显微镜观察表明，所获得的Bi，Ag 2 Te，Bi 2 Te 3，Sb 2 Te 3，CdTe和NiTe 1.5纳米晶体具有纳米范围内的晶粒尺寸。根据吉布斯自由能和电极电位的计算，用热力学判据解释了用这种方法可以得到的金属相和半导体相的类型。提出最终产物的晶相是由金属氧化物与还原性气体反应的吉布斯自由能和金属氧化物氧化还原电极电位的变化控制的，而不是金属氧化还原标准电极电位和元素的电负性。并对其它二元、三元化合物的制备提出了预测。我们的研究结果为半导体和金属纳米晶的简易和绿色制备提供了新的见解。
This work reports the intrinsic thermodynamical criterion for the preparation of metal and semiconductor nanocrystals using a polymerized complexing method. The basic principle of this method is the formation of a polymerized complexing structure between mono-, binary-, or ternary-metallic ions and bonding agents in aqueous or ethylene glycol solutions by evaporation of the solvents. Heat treatment of the complexing structure under N2 atmosphere produces H2 and CH4 gases, which can reduce the oxide crystalline nuclei to semiconductor and metallic nanocrystals. Experimental results show that Te, CdTe, Ag2Te, CuTe, NiTe1.5, CoTe1.5, Bi2Te3, Sb2Te3, Bi-Sb, In2Te3, Ni2.9SnTe2, CuGaTe2, and CuInS2 semiconductors and Bi, Sb, Ag, Cu, and Ni metallic nanocrystals can be prepared by this method. Transmission electron microscopy observations show that the obtained Bi, Ag2Te, Bi2Te3, Sb2Te3, CdTe, and NiTe1.5 nanocrystals have grain sizes in the nanometer range. The types of metallic and semiconductor phase that can be obtained by this method are explained by the thermodynamical criterion based on calculations of the Gibbs free energy and electrode potential. It is proposed that the crystalline phase of the final product is controlled by the change of the Gibbs free energies of the reactions of the metal oxide with reducing gases and the metal oxide redox electrode potentials, not the metal redox standard electrode potentials and electronegativities of the elements. Furthermore, a prediction is presented for the preparation of other kinds of binary and ternary compound based on the thermodynamical criterion. Our results provide new insight into facile and green preparation of semiconductor and metal nanocrystals.