Unknown aspects of self-assembly of PbS microscale superstructures.
Unknown aspects of self-assembly of PbS microscale superstructures.
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DOI：
10.1021/nn300890s
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发表时间：
2012-05-22
期刊：
影响因子：
17.1
通讯作者：
Kotov NA
中科院分区：
文献类型：
--
作者：
Querejeta-Fernández A;Hernández-Garrido JC;Yang H;Zhou Y;Varela A;Parras M;Calvino-Gámez JJ;González-Calbet JM;Green PF;Kotov NA
纳米粒子（NP）自组装（SA）的许多有趣和复杂的例子是已知的。从基础和技术的角度来看，这一领域需要在三个主要方向上取得进展：a）理解三维（3D）SA的机制和驱动力与纳米和微观层次的组织; B）理解拆卸/解构过程;和c）找到组装成连续的上层建筑没有绝缘障碍的合成方法。从这个角度来看，我们研究了著名的恒星状PbS超结构的形成，并发现了一些以前未知或被忽视的方面，可以在这三个方向上推进NP自组装的知识。主要的一个是，形成大的表面上单晶的PbS超结构与多层次的八面体对称性可以解释只有SA的小八面体NP。我们发现PbS超支化星的形成经历了五个不同的阶段：1）早期PbS纳米粒子的成核，平均直径为31 nm; 2）组装成100-500 nm的八面体介晶; 3）组装成1000-2500 nm的超支化星; 4）组装和离子重结晶成六臂棒，伴随着精细纳米结构的消失; 5）解构为棒状和立方八面体NP。在组装模式之间的切换期间发生由于模式决定力，包括范德华力和静电（电荷-电荷，偶极-偶极和极化）相互作用的变量主导。超结构的解构是由作为介质的低共熔溶剂（DES）中的化学变化引发的。PbS超结构可以是纳米级组织的基础研究和SA制造（光）电子和能量收集设备，需要在多个尺度上组织PbS组件的优秀模型。
A lot of interesting and sophisticated examples of nanoparticle (NP) self-assembly (SA) are known. From both fundamental and technological standpoints this field requires advancements in three principle directions: a) understanding the mechanism and driving forces of three-dimensional (3D) SA with both nano- and micro-levels of organization; b) understanding of disassembly/deconstruction processes; and c) finding synthetic methods of assembly into continuous superstructures without insulating barriers. From this perspective, we investigated the formation of well-known star-like PbS superstructures and found a number of previously unknown or overlooked aspects that can advance the knowledge of NP self-assembly in these three directions. The primary one is that the formation of large seemingly monocrystalline PbS superstructures with multiple levels of octahedral symmetry can be explained only by SA of small octahedral NPs. We found five distinct periods in the formation PbS hyperbranched stars: 1) nucleation of early PbS NPs with an average diameter of 31 nm; 2) assembly into 100–500 nm octahedral mesocrystals; 3) assembly into 1000–2500 nm hyperbranched stars; 4) assembly and ionic recrystallization into six-arm rods accompanied by disappearance of fine nanoscale structure; 5) deconstruction into rods and cubooctahedral NPs. The switches in assembly patterns between the periods occur due to variable dominance of pattern–determining forces that include vander Waals and electrostatic (charge-charge, dipole-dipole, and polarization) interactions. The superstructure deconstruction is triggered by chemical changes in the deep eutectic solvent (DES) used as the media. PbS superstructures can be excellent models for fundamental studies of nanoscale organization and SA manufacturing of (opto)electronics and energy harvesting devices which require organization of PbS components at multiple scales.
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影响因子：
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