Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: POSTERS Nanoparticles

CPP 14.6: Poster

Tuesday, March 24, 2009, 14:00–16:30, P3

Spectroscopic fingerprints of photodegrading CdSe/ZnS quantum dots — •Danny Kowerko, Jörg Schuster, and Christian von Borczyskowsi — Center of nanostructured materials and analytics, TU-Chemnitz, 09107 Chemnitz

Colloidal semiconductor nanocrystals have been under investigation for more than a decade with a growing field of applications in science and industry. However, photophysics and chemistry are still not fully understood, since crystal structure of core and shell as well as ligands may vary slightly between different charges, thus yielding individual optical properties even of single quantum dots from the same stock. We will discuss the role of surface (states) and its defined modification (e.g. by functionalized dye molecules) with special regard to nanocrystal degradation processes which are obviously accompanied by distinct spectral shifts and lifetime alterations. Besides time resolved ensemble studies in solution, we have chosen a multiparameter single particle approach, giving insight to spectral and luminescence lifetime fluctuations of individual quantum dots. Comparison of individual - on SiO2 immobilized - untreated and modified species will provide a deeper insight towards the underlying mechanisms of surface manipulation induced photodegradation and thus allow for a correlation with the ensemble results.