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1 June 2005 Structure and excited state relaxation dynamics in nanoscale self-assembled arrays: multiporphyrin complexes, porphyrin-quantum dot composites
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Proceedings Volume 5849, Fifth Workshop on Atomic and Molecular Physics; (2005) https://doi.org/10.1117/12.629399
Event: Fifth Workshop on Atomic and Molecular Physics, 2004, Jurata, Poland
Abstract
Self-assembled nanoscale arrays of controllable geometry and composition (up to 8 tetrapyrroles) have been formed via non-covalent binding interactions of the meso-phenyl bridged Zn-octaethylporphyrin chemical dimers or trimers with di- /tetrapyridyl substituted porphyrin extra-ligands. In these complexes using steady-state and time-resolved (ps fluorescence and fs pump-probe) measurements pathways and efficiencies of the energy transfer photoinduced charge separation as well as exchange d-π effects have been studied in solutions of variable polarity at 77-293 K. The same principles of aggregation via the key-hole scheme "Zn-pyridyl" have been used also for the surface passivation of pyridylsubstituted tetrapyrroles on the coreshell semiconductor CdSe/ZnS quantum dots (QD) showing quantum confinement effects. Picosecond time-resolved and steady-state data reveal that CdSe/ZnS QD emission is multiexponential and the efficiency of its quenching by attached porphyrins (due to energy transfer and photoinduced charge separation) depends strongly on the number of anchoring groups their arrangement in the porphyrin molecule as well as on QD size and number of ZnS monolayers. The analysis of spectroscopic and kinetic findings reveals that on average only ~l/5 porphyrin molecules are assembled on the QD and a limited number of "vacancies" accessible for porphyrin attachment is available on the QD surface.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
E. I. Zenkevich and C. von Borczyskowski "Structure and excited state relaxation dynamics in nanoscale self-assembled arrays: multiporphyrin complexes, porphyrin-quantum dot composites", Proc. SPIE 5849, Fifth Workshop on Atomic and Molecular Physics, (1 June 2005); https://doi.org/10.1117/12.629399
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