Ultrahigh Density Arrays of Toroidal ZnO Nanostructures by One-Step Cooperative Self-Assembly Processes: Mechanism of Structural Evolution and Hybridization with Au Nanoparticles

2011 ◽  
Vol 17 (7) ◽  
pp. 2068-2076 ◽  
Author(s):  
Yoon Hee Jang ◽  
Seung Yun Yang ◽  
Yu Jin Jang ◽  
Cheolmin Park ◽  
Jin Kon Kim ◽  
...  
2012 ◽  
Vol 7 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Shakiela Begum ◽  
Ian P. Jones ◽  
Daniel E. Lynch ◽  
Jon A. Preece

2008 ◽  
Vol 01 (01) ◽  
pp. 43-53 ◽  
Author(s):  
YU XIN ZHANG ◽  
HUA CHUN ZENG

We present a systematic investigation on the roles of some starting reagents commonly used in gold nanoparticle synthesis. Our results show that Au nanoparticles adsorbed with tetraoctylammonium bromide (TOAB) or TOAB and 1-dodecanethiol (DDT) can self-assemble into spherical aggregates in various hierarchical forms, such as discrete, linear, and two-dimensional arrays, without using any additional structural linkers. Interestingly, aged Au nanoparticles in different interconnected spherical aggregates are highly ordered, showing long-range lattice uniformity. On the basis of our substrate-dependent experiments, it has been revealed that the sphere formation, self-assembly, and crystallization of Au nanoparticles in the superlattice take place upon drying. A structural evolution of mesoscale spherical assemblies to planar organizations of Au nanoparticles has also been revealed in this work for the first time. In general, the Au nanoparticles are better shelled with TOAB than with DDT surfactant. The symmetrical organic shells of TOAB and its multi-chain structure are believed to be responsible for the high capacity of particle aggregation as well as for the long-range assembling order.


2019 ◽  
Author(s):  
Mark Workentin ◽  
François Lagugné-Labarthet ◽  
Sidney Legge

In this work we present a clean one-step process for modifying headgroups of self-assembled monolayers (SAMs) on gold using photo-enabled click chemistry. A thiolated, cyclopropenone-caged strained alkyne precursor was first functionalized onto a flat gold substrate through self-assembly. Exposure of the cyclopropenone SAM to UV-A light initiated the efficient photochemical decarbonylation of the cyclopropenone moiety, revealing the strained alkyne capable of undergoing the interfacial strain-promoted alkyne-azide cycloaddition (SPAAC). Irradiated SAMs were derivatized with a series of model azides with varied hydrophobicity to demonstrate the generality of this chemical system for the modification and fine-tuning of the surface chemistry on gold substrates. SAMs were characterized at each step with polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to confirm successful functionalization and reactivity. Furthermore, to showcase the compatibility of this approach with biochemical applications, cyclopropenone SAMs were irradiated and modified with azide-bearing cell adhesion peptides to promote human fibroblast cell adhesion, then imaged by live cell fluorescence microscopy. Thus, the “photoclick” methodology reported here represents an improved, versatile, catalyst-free protocol that allows for a high degree of control over the modification of material surfaces, with applicability in materials science as well as biochemistry.<br>


2021 ◽  
Vol 60 ◽  
pp. 194-201
Author(s):  
Haonan Ren ◽  
Lingxiao Yu ◽  
Leping Yang ◽  
Zheng-Hong Huang ◽  
Feiyu Kang ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1502
Author(s):  
Johannes M. Parikka ◽  
Karolina Sokołowska ◽  
Nemanja Markešević ◽  
J. Jussi Toppari

The predictable nature of deoxyribonucleic acid (DNA) interactions enables assembly of DNA into almost any arbitrary shape with programmable features of nanometer precision. The recent progress of DNA nanotechnology has allowed production of an even wider gamut of possible shapes with high-yield and error-free assembly processes. Most of these structures are, however, limited in size to a nanometer scale. To overcome this limitation, a plethora of studies has been carried out to form larger structures using DNA assemblies as building blocks or tiles. Therefore, DNA tiles have become one of the most widely used building blocks for engineering large, intricate structures with nanometer precision. To create even larger assemblies with highly organized patterns, scientists have developed a variety of structural design principles and assembly methods. This review first summarizes currently available DNA tile toolboxes and the basic principles of lattice formation and hierarchical self-assembly using DNA tiles. Special emphasis is given to the forces involved in the assembly process in liquid-liquid and at solid-liquid interfaces, and how to master them to reach the optimum balance between the involved interactions for successful self-assembly. In addition, we focus on the recent approaches that have shown great potential for the controlled immobilization and positioning of DNA nanostructures on different surfaces. The ability to position DNA objects in a controllable manner on technologically relevant surfaces is one step forward towards the integration of DNA-based materials into nanoelectronic and sensor devices.


2007 ◽  
Vol 1057 ◽  
Author(s):  
Abhishek Prasad ◽  
Samuel Mensah ◽  
Jiesheng Wang ◽  
Archana Pandey ◽  
Yoke Khin Yap

ABSTRACTThe growth of ZnO nanotubes and nanosquids is obtained by conventional thermal chemical vapor deposition (CVD) without the use of catalysts or templates. Characterization of these ZnO nanostructures was conducted by X-ray powder diffraction (XRD), Field-emission scanning electron microscopy (FESEM), Raman spectroscopy, and photoluminescence (PL). Results indicate that these ZnO nanostructures maintain the crystalline structures of the bulk wurtzite ZnO crystals. Our results show that rapid cooling can be used to induce the formation of ZnO nanotubes and ZnO nanosquids. The self-assembly of these novel ZnO nanostructures are guided by the theory of nucleation and the vapor-solid crystal growth mechanism.


2012 ◽  
Vol 12 (10) ◽  
pp. 4829-4833 ◽  
Author(s):  
Xiaobin Xu ◽  
Min Wu ◽  
Michael Asoro ◽  
P. J. Ferreira ◽  
D. L. Fan

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Shira Yochelis ◽  
Eran Katzir ◽  
Yoav Kalcheim ◽  
Vitaly Gutkin ◽  
Oded Millo ◽  
...  

Many intriguing aspects of molecular electronics are attributed to organic-inorganic interactions, yet charge transfer through such junctions still requires fundamental study. Recently, there is a growing interest in anchoring groups, which considered dominating the charge transport. With this respect, we choose to investigate self-assembly of disilane molecules sandwiched between gold surface and gold nanoparticles. These assemblies are found to exhibit covalent bonds not only between the anchoring Si groups and the gold surfaces but also in plane crosslinks that increase the monolayer stability. Finally, using scanning tunneling spectroscopy we demonstrate that the disilane molecules provide strong electrical coupling between the Au nanoparticles and a superconductor substrate.


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