Publications

2014
Amit Halevi, Shira Halivni, Meirav Oded, Axel HE Müller, Uri Banin, and Roy Shenhar. 2014. “Co-assembly of A–B diblock copolymers with B′-type nanoparticles in thin films: effect of copolymer composition and nanoparticle shape.” Macromolecules, 47, 9, Pp. 3022-3032. Publisher's Version Abstract

 

41. co-assembly of B'-type nanorods in A-B block copolymers

The coassembly of A B diblock copolymers with B'-type nanoparticles (i.e., nanoparticles that are slightly incompatible with the B domain) leads to hierarchical structures, where the block copolymer phase separates first and the nanoparticles create close-packed arrays within the B domains due to a slower, secondary phase separation process. Here we report the results of a comprehensive study, which focused on two aspects: the influence of the nanoparticle shape (spherical vs rod-like) and the effect of the volume composition of the blocks. Three polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) copolymers featuring similar molecular weights but differing in PS volume fraction were mixed with spherical and rod-shaped poly(ethylene oxide)- (PEO-) capped CdS nanoparticles at different filling fractions and cast as thin films. Our results highlight the mutual influence between the block copolymer and the nanoparticles on the resulting morphology, demonstrating the ability to control the film morphology by the filling fraction of the nanoparticles and their tendency to localize at the film surface, and by confinement-induced nanoparticle aggregation. Most importantly, the results reveal the influence of the nanoparticle shape on the structure of the film.

Guohua Jia and Uri Banin. 2014. “A general strategy for synthesizing colloidal semiconductor zinc chalcogenide quantum rods.” Journal of the American Chemical Society, 136, 31, Pp. 11121-11127. Publisher's Version Abstract

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Quasi-one-dimensional (1D) semiconductor nanocrystals manifest linearly polarized emission, reduced lasing threshold, and improved charge transport compared with their counterparts such as spherical quantum dots. Present investigations of colloidal semiconductor quantum rods are mainly based on cadmium chalcogenide systems because of their facile synthetic accessibility. However, it is still a big challenge to fabricate quasi-1D zinc chalcogenide nanocrystals with controlled aspect ratios. Here we report a general strategy for synthesizing zinc chalcogenide quantum rods via a colloidal chemical synthetic approach. Unlike the most common growth mechanisms of quasi-1D colloidal nanocrystals such as monomer attachment and particle coalescence, the synthesis of zinc chalcogenide quantum rods is performed by a ripening process starting from their respective ultrathin nanowires through thermodynamically driven material diffusion. We anticipate that this strategy is general and could be applied to other systems to construct quasi-1D nanostructures. Moreover, the presence of cadmium-free (or “green”) zinc chalcogenide quantum rods synthesized through this strategy provides a desirable platform for eco-friendly photocatalysis, optoelectronic devices, biolabeling, and other applications.

Uri Banin, Yuval Ben-Shahar, and Kathy Vinokurov. 2014. “Hybrid semiconductor–metal nanoparticles: from architecture to function.” Chemistry of Materials, 26, 1, Pp. 97-110.
Shlomit Kraus‐Ophir, Yuval Ben‐Shahar, Uri Banin, and Daniel Mandler. 2014. “Perpendicular Orientation of Anisotropic Au‐Tipped CdS Nanorods at the Air/Water Interface.” Advanced Materials Interfaces, 1, 1, Pp. 1300030.
Kathy Vinokurov, Yehonadav Bekenstein, Vitaly Gutkin, Inna Popov, Oded Millo, and Uri Banin. 2014. “Rhodium growth on Cu 2 S nanocrystals yielding hybrid nanoscale inorganic cages and their synergistic properties.” CrystEngComm, 16, 40, Pp. 9506-9512.
Roy Shenhar, Uri Banin, Elina Ploshnik, and Asaf Salant. 2014. “Assemblies comprising block co-polymer films and nanorods.” United States of America.
Guohua Jia, Amit Sitt, Gal B Hitin, Ido Hadar, Yehonadav Bekenstein, Yorai Amit, Inna Popov, and Uri Banin. 2014. “Couples of colloidal semiconductor nanorods formed by self-limited assembly.” Nature materials, 13, 3, Pp. 301. Publisher's Version Abstract

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Colloidal nanocrystal synthesis provides a powerful approach for creating unique nanostructures of relevance for applications. Here, we report that wurtzite ZnSe nanorod couples connected by twinning structures can be synthesized by means of a self-limited assembly process. Unlike for individual nanorods, the band-edge states calculated for the nanorod couples are predominantly confined to the short edges of the structure and this leads to low photoluminescence polarization anisotropy, as confirmed by single-particle fluorescence. Through a cation-exchange approach, the composition of nanorod couples can be readily expanded to additional materials, such as CdSe and PbSe. We anticipate that this family of nanorod-couple structures with distinct compositions and controlled properties will constitute an ideal system for the investigation of electronic coupling effects between individual nanorod components on the nanoscale, with relevance to applications in optics, photocatalysis and optoelectronic devices.

Uri Banin, Shlomo Yitzchaik, Ori Cheshnovsky, Yael Hanein, and Evelyne Sernagor. 2014. “Photoelectrical devices for stimulating neurons.” United States of America.
Lilach Bareket, Nir Waiskopf, David Rand, Gur Lubin, Moshe David-Pur, Jacob Ben-Dov, Soumyendu Roy, Cyril Eleftheriou, Evelyne Sernagor, and Ori Cheshnovsky. 2014. “Semiconductor nanorod–carbon nanotube biomimetic films for wire-free photostimulation of blind retinas.” Nano letters, 14, 11, Pp. 6685-6692. Publisher's Version Abstract

We report the development of a semiconductor nanorod-carbon nanotube based platform for wire-free, light induced retina stimulation. A plasma polymerized acrylic acid midlayer was used to achieve covalent conjugation of semiconductor nanorods directly onto neuro-adhesive, threedimensional carbon nanotube surfaces. Photocurrent, photovoltage, and fluorescence lifetime measurements validate efficient charge transfer between the nanorods and the carbon nanotube films. Successful stimulation of a light-insensitive chick retina suggests the potential use of this novel platform in future artificial retina application