Publications

2013
Amit Sitt, Na’ama Even-Dar, Shira Halivni, Adam Faust, Lior Yedidya, and Uri Banin. 2013. “Analysis of shape and dimensionality effects on fluorescence resonance energy transfer from nanocrystals to multiple acceptors.” The Journal of Physical Chemistry C, 117, 43, Pp. 22186-22197. Publisher's Version Abstract

The dynamic process of energy transfer from semiconductor nanocrystals acting as donors to multiple acceptors attached to their surface emerges as an important tool for probing the nanoparticle environment in the nanometric scale. Understanding the underlying principles which govern the dynamics of the energy transfer process, and in particular the role of the shape and dimensions of the nanocrystal in determining it, is crucial for utilizing it for a range of applications including sensing, biolabeling, and energy funneling. We describe and theoretically analyze the temporal behavior of energy transfer from core/shell spherical dot, dot in a rod, and dot in a pod nanocrystals to multiple acceptors linked to their surface. Using a modified restricted geometries model, we evaluate the different parameters which affect the energy transfer and demonstrate the role of the nanocrystal geometry and dimensions in determining the dynamics of the energy transfer process. The modeled dynamics show good agreement to experimental data measured for spherical and dot in a rod nanocrystals. The results obtained from the model indicate that energy transfer may be used for extracting the dimensions and dimensionalities of nanocrystals and for probing real-time processes in the ensemble level, which are relevant for characterization and sensing applications.

Amit Sitt, Ido Hadar, and Uri Banin. 2013. “Band-gap engineering, optoelectronic properties and applications of colloidal heterostructured semiconductor nanorods.” Nano Today, 8, 5, Pp. 494-513.
Yorai Amit, Adam Fasut, Oded Milo, Eran Rabani, Anatoly Frenkel, and Uri Banin. 2013. “How to Dope a Semiconductor Nanocrystal.” ECS Transactions, 58, 7, Pp. 127.
Nir Waiskopf, Rany Rotem, Itzhak Shweky, Lior Yedidya, Hermona Soreq, and Uri Banin. 2013. “Labeling Acetyl-and Butyrylcholinesterase Using Semiconductor Nanocrystals for Biological Applications.” BioNanoScience, 3, 1, Pp. 1-11.
Ido Hadar, Gal B Hitin, Amit Sitt, Adam Faust, and Uri Banin. 2013. “Polarization properties of semiconductor nanorod heterostructures: From single particles to the ensemble.” The journal of physical chemistry letters, 4, 3, Pp. 502-507. Publisher's Version Abstract

Abstract Image

Semiconductor heterostructured seeded nanorods exhibit intense polarized emission, and the degree of polarization is determined by their morphology and dimensions. Combined optical and atomic force microscopy were utilized to directly correlate the emission polarization and the orientation of single seeded nanorods. For both the CdSe/CdS sphere-in-rod (S@R) and rod-in-rod (R@R), the emission was found to be polarized along the nanorod’s main axis. Statistical analysis for hundreds of single nanorods shows higher degree of polarization, p, for R@R (p = 0.83), in comparison to S@R (p = 0.75). These results are in good agreement with the values inferred by ensemble photoselection anisotropy measurements in solution, establishing its validity for nanorod samples. On this basis, photoselection photoluminescence excitation anisotropy measurements were carried out providing unique information concerning the symmetry of higher excitonic transitions and allowing for a better distinction between the dielectric and the quantum-mechanical contributions to polarization in nanorods.

Yorai Amit, Hagai Eshet, Adam Faust, Anitha Patllola, Eran Rabani, Uri Banin, and Anatoly I Frenkel. 2013. “Unraveling the impurity location and binding in heavily doped semiconductor nanocrystals: The case of Cu in InAs nanocrystals.” The Journal of Physical Chemistry C, 117, 26, Pp. 13688-13696. Publisher's Version Abstract

The doping of colloidal semiconductor nanocrystals (NCs) presents an additional knob beyond size and shape for controlling the electronic properties. An important problem for doping with aliovalent elements is associated with resolving the location of the dopant and its structural surrounding within small NCs, an issue directly connected with self-purification. Here we used a postsynthesis diffusion-based doping method for introducing Cu impurities into InAs quantum dots. X-ray absorption fine structure (XAFS) spectroscopy experiments along with first-principle density functional theory (DFT) calculations were used to probe the impurity sites. The concentration dependence was investigated for a wide range of doping levels, helping to derive a self-consistent picture where the Cu impurity occupies an interstitial site within the InAs lattice. Moreover, at extremely high doping levels, Cu–Cu interactions are identified in the XAFS data. This structural model is supported by X-ray diffraction data, along with the DFT calculation. These findings establish the reproducibility of the diffusion-based doping strategy giving rise to new opportunities of correlating the structural details with emerging electronic properties in heavily doped NCs.

Uri Banin, Adiel Zimran, Itai Lieberman, and Amit Sitt. 2013. “Anistropic semiconductor nanoparticles.” United States of America.
Mark J Polking, Prashant K Jain, Yehonadav Bekenstein, Uri Banin, Oded Millo, Ramamoorthy Ramesh, and Paul A Alivisatos. 2013. “Controlling localized surface plasmon resonances in GeTe nanoparticles using an amorphous-to-crystalline phase transition.” Physical review letters, 111, 3, Pp. 037401. Publisher's Version Abstract

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Infrared absorption measurements of amorphous and crystalline nanoparticles of GeTe reveal a localized surface plasmon resonance (LSPR) mode in the crystalline phase that is absent in the amorphous phase. The LSPR mode emerges upon crystallization of amorphous nanoparticles. The contrasting plasmonic properties are elucidated with scanning tunneling spectroscopy measurements indicating a Burstein-Moss shift of the band gap in the crystalline phase and a finite density of electronic states throughout the band gap in the amorphous phase that limits the effective free carrier density.

Uri Banin, Yuval Ben-Shahar, and Kathy Vinokurov. 2013. “Hybrid semiconductor–metal nanoparticles: from architecture to function.” Chemistry of Materials, 26, 1, Pp. 97-110. Publisher's Version Abstract

Hybrid nanoparticles combine two or more disparate materials on the same nanosystem and represent a powerful approach for achieving advanced materials with multiple functionalities stemming from the unusual materials combinations. This review focuses on recent advances in the area of semiconductor–metal hybrid nanoparticles. Synthesis approaches offering high degree of control over the number of components, their compositions, shapes, and interfacial characteristics are discussed, including examples of advanced architectures. Progress in hybrid nanoscale inorganic cage structures prepared by a selective edge growth mechanism of the metal onto the semiconductor nanocrystal is also presented. The combined and often synergistic properties of the hybrid nanoparticles are described with emphasis on optical properties, electronic structure, electrical characteristics, and light induced charge separation effects. Progress toward the application of hybrid nanoparticles in photocatalysis is overviewed. We conclude with a summary and point out some challenges for further development and understanding of semiconductor–metal hybrid nanoparticles. This progress shows promise for application of hybrid nanoparticles in photocatalysis, catalysis, optical components, and electronic devices.

 

Uri Banin and Assaf Aharoni. 2013. “III-V semiconductor core-heteroshell nanocrystals.” United States of America.
Uri Banin, Volker Hilarius, Assaf Aharoni, and Hagai Arbell. 2013. “Optical display device and method thereof.” United States of America. Publisher's Version Abstract

The present invention provides and optical display device and a method for use in displaying an image. The optical display device comprises An optical display device comprising: at least one region of nanostructures operable as an optically active media, such that said nanostructures are responsive to input electromagnetic radiation to emit output electromagnetic radiation, and an arrangement of electrodes being configured and operable to be selectively addressable to create an external electric field to said at least one region of nanostructures, said region of nanostructures and said arrangement of electrodes defining together a pixel arrangement of said display device; said external electric field affecting said at least one region of nanostructures to selectively modulate emission of said output electromagnetic radiation, said output electromagnetic radiation being an output of at least one pixel element of the display device.

Hagai Arbell, Assaf Aharoni, and Uri Banin. 2013. “Phosphor-nanoparticle combinations.” United States of America.