Organometallic synthesis, structure determination, shape evolution, and formation mechanism of hexapod-like ternary PbSe(x)S(1-x) nanostructures with tunable compositions.
Organometallic synthesis, structure determination, shape evolution, and formation mechanism of hexapod-like ternary PbSe(x)S(1-x) nanostructures with tunable compositions.
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DOI：
10.1021/la501267f
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发表时间：
2014-06
期刊：
影响因子：
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通讯作者：
Genrong Shao;Guihuan Chen;J. Zuo;Ming Gong;Qing Yang
中科院分区：
文献类型：
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作者：
Genrong Shao;Guihuan Chen;J. Zuo;Ming Gong;Qing Yang
报道了通过一种替代的有机金属路线制备六足状三元PbSexS 1-x纳米结构，该路线由Pb（II）盐与三苯基膦硒化物（Ph 3 PSe）和二苄基二硫化物（DBDS）在二苄胺（DBA）中在260 °C下加入油酸（OA）反应。采用XRD、SEM、TEM、拉曼、HRTEM、SAED、XPS、EDX和HAADF-STEM等技术对产物的形貌、结构和组成进行了表征，结果表明，所得三元纳米六足结构为典型的岩盐相，具有富铅特征，无相分离，其组成可通过简单的反应参数进行系统调控。研究表明，通过有效地选择在当前反应体系中具有相似反应活性的Ph 3 PSe和DBDS的Se和S源，沿着PbSe和PbS两个端元之间的小晶格失配，成功地制备了具有可调组成的三元六足结构.一般来说，在DBA中获得的三元纳米结构的组成和晶格参数之间的关系与不同的添加OA表现出线性斜率，以及与Vegard定律一致。有趣的是，深入的研究表明，纳米结构主要是梯度合金化的纳米结构与一些硫族元素的偏析或障碍，而不是均匀合金化的固态溶液，由于动力学限制短的反应时间，即使热力学是可行的系统，而且，在原料中的S元素的浓度高，往往在三元纳米结构中的相对高密度的障碍。在揭示不同微观结构的纳米结构形成机理的基础上，通过延长反应时间，可以将三元PbSexS_（1-x）六足结构从具有偏析的梯度合金调整到近似均匀的六足结构。此外，通过拉曼检测，在环境条件下证明了纳米结构光解为硫酸铅和硒酸铅物质，尽管它们在-190 °C下是稳定的。
The fabrication of hexapod-like ternary PbSexS1-x nanostructures has been reported via an alternative organometallic route from reaction of Pb(II) salt with triphenylphosphine selenide (Ph3PSe) and dibenzyl disulfide (DBDS) in dibenzylamine (DBA) with addition of oleic acid (OA) at 260 °C. The shape, structure, and composition of the nanostructured hexapods are investigated and determined by techniques of XRD, SEM, TEM, Raman, HRTEM, SAED, XPS, EDX, and HAADF-STEM, and the obtained ternary nanostructured hexapods are of typical rock salt phase with Pb-rich features without phase separation, and their compositions could be systematically regulated by facile variations of reaction parameters. Investigations reveal that the successful fabrication of the ternary hexapods with tunable compositions is resulted from the effective selection of Se and S sources of Ph3PSe and DBDS that have similar reactivity in the current reaction system along with small lattice mismatch between the two end members of PbSe and PbS. Generally, the relations between the composition and lattice parameters for the ternary nanostructures obtained in DBA with varied addition of OA exhibit linear slops that are consistent well with Vegard's law. Interestingly, intensive investigations show that the nanostructures are mainly gradiently alloyed nanostructures with somewhat chalcogen-element segregations or disorders rather than homogeneously alloyed solid-state solutions due to kinetic limitation for short reaction time even though thermodynamics is feasible in the system, and also, high concentration of S element in the feedstocks tends to relative high density of disorders in the ternary nanostructures. Based on the revealing of the formation mechanism for the nanostructures with varied microstructures, the ternary PbSexS1-x hexapods can be tuned from gradient alloys with segregations to approximately homogeneous via enlongating reaction time. In addition, the photolysis of the nanostructures to lead oxysulfate and oxyselenate species is evidenced at ambient condition via Raman detection although they are stable at -190 °C.