Structure of CdSe Quantum Rods

An additional system prepared by colloidal chemistry which continues to attract considerable interest is that of QRs that exhibit electronic and optical properties that differ from those of QDs. For example, due to their cylindrical symmetry, QRs have a linearly polarized emission, as demonstrated by fluorescence measurements on single rods [41], leading to polarized lasing [14]. The powerful combination of optical and turmeling spectroscopy discussed here was also applied to investigations of the length- and diameter-dependence of the electronic level stmcture of CdSe QRs [40]. 

6 Level Structure and Band-Oflsets in Heterostructured Seeded Quantum Rods 

This approach was appUed to heterostructured seeded nanorods, both for CdSe-CdS (type I) and for ZnSe-CdS QD/QR core-shell nanocrystals. The former system was studied extensively, using a variety of optical spectroscopy methods the data acquired suggested a charge separation, where the hole is located in the QlSe core [positioned close to one end of the nanorod (NR)j and the electron extends over the CdS shell [84]. This picture is consistent with a small value of the conduction band offset, typically Ac 0.2eV, extracted from the bulk regime. However, a direct measurement of the band offsets and the consequent charge distribution in such nanocrystals is of major interest 

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