Semiconductor quantum dots possess attractive optical properties useful in the photonic field. Thanks to the evolution of core-shell colloidal synthesis, quantum dots exhibit almost ideal emitting properties. Their employment in optoelectronic devices is encouraged by their size-tunable emission as well as by their high absorption cross-section and high photoluminescence quantum yield. In this work, starting from the archetypal CdSe based system, the influence of shell thickness and composition on exciton dynamics in CdSe/CdxZn1-xScore-shell QDs is investigated. By means of steadystate and transient optical spectroscopy, single-and multi-exciton recombination processes are characterized and correlated with different shell materials. The present study clarifies why graded CdSe-CdS-Cd0.5Zn0.5-ZnS core-shell represents the best performing heterostructure for optical gain applications, since such quantum dots combine the high radiative rates of CdS with the superior confinement potential of ZnS in a single dot.
Minotto, A., Todescato, F., Signorini, R., Jasieniak, J., Bozio, R. (2014). Influence of core-shell interfaces on exciton and multi-exciton dynamics of CdSe-CdxZn1-xS quantum dots. In Proceedings of SPIE - The International Society for Optical Engineering. SPIE [10.1117/12.2060973].
Influence of core-shell interfaces on exciton and multi-exciton dynamics of CdSe-CdxZn1-xS quantum dots
Minotto, A;
2014
Abstract
Semiconductor quantum dots possess attractive optical properties useful in the photonic field. Thanks to the evolution of core-shell colloidal synthesis, quantum dots exhibit almost ideal emitting properties. Their employment in optoelectronic devices is encouraged by their size-tunable emission as well as by their high absorption cross-section and high photoluminescence quantum yield. In this work, starting from the archetypal CdSe based system, the influence of shell thickness and composition on exciton dynamics in CdSe/CdxZn1-xScore-shell QDs is investigated. By means of steadystate and transient optical spectroscopy, single-and multi-exciton recombination processes are characterized and correlated with different shell materials. The present study clarifies why graded CdSe-CdS-Cd0.5Zn0.5-ZnS core-shell represents the best performing heterostructure for optical gain applications, since such quantum dots combine the high radiative rates of CdS with the superior confinement potential of ZnS in a single dot.
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