Publications

2013
Sitt, A. ; Hadar, I. ; Banin, U. . Band-Gap Engineering, Optoelectronic Properties And Applications Of Colloidal Heterostructured Semiconductor Nanorods. NANO TODAY 2013, 8, 494-513. Abstract

A fascinating phenomenon which characterizes semiconductors in the nanoscale regime is the ability to control the physical properties of the system through its dimensionality, as was demonstrated for a large number of systems including 2D quantum wells, 1D nanowires, and 0D quantum dots. Heterostructured nanorods, which are composed of two or more semiconductors, present an exciting example for a system in which the physical properties are strongly influenced by the 1D nature of the entire particle, but also incorporate the effects of the dimensionality, dimensions, and composition of each component on its own.

The ongoing progress in colloidal synthesis of nanocrystals allows nowadays to synthesize a variety of heterostructured nanorods with different compositions and structures, ranging from seeded nanorods to rods with asymmetric spatial compositions. The unique properties of these systems, with reduced and mixed dimensionality, attract a growing interest from the scientific point of view, and are also attractive for a range of applications including solid state lighting, lasers, light emitting diodes, flat panel displays, bio-labeling, and solar cells.

In this paper we review the growing family of heterostructured nanorods, analyze the factors which determine their physical properties and in particular their optical characteristics, and discuss the potential applications of these systems in different technologies.

Hadar, I. ; Hitin, G. B. ; Sitt, A. ; Faust, A. ; Banin, U. . Polarization Properties Of Semiconductor Nanorod Heterostructures: From Single Particles To The Ensemble. JOURNAL OF PHYSICAL CHEMISTRY LETTERS 2013, 4, 502-507. Abstract
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.
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