부산대학교 도서관

Nonblinking excitonic emission from near-infrared andtype-II nanocrystalquantum dots (NQDs) is reported for the first time. To realize thisunusual degree of stability at the single-dot level, novel InP/CdScore/shell NQDs were synthesized for a range of shell thicknesses(∼1–11 monolayers of CdS). Ensemble spectroscopy measurements(photoluminescence peak position and radiative lifetimes) and electronicstructure calculations established the transition from type-I to type-IIband alignment in these heterostructured NQDs. More significantly,single-NQD studies revealed clear evidence for blinking suppressionthat was not strongly shell-thickness dependent, while photobleachingand biexciton lifetimes trended explicitly with extent of shelling.Specifically, very long biexciton lifetimesup to >7 nswereobtained for the thickest-shell structures, indicating dramatic suppressionof nonradiative Auger recombination. This new system demonstratesthat electronic structure and shell thickness can be employed togetherto effect control over key single-dot and ensemble NQD photophysicalproperties. [ABSTRACT FROM AUTHOR]