Polarization Properties of Semiconductor Nanorod Heterostructures: From Single Particles to the Ensemble.
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.
Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
Ido
I
Hadar
Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
Gal B
GB
Hitin
Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
Amit
A
Sitt
Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
Adam
A
Faust
Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
Uri
U
Banin
anisotropy; atomic force microscopy; fluorescence; heterostructure; nanorod; polarization; single particle microscopy