White-light-emitting CdSe quantum dots with magic size via one-pot synthesis approach

Two stable magic-sized CdSe families were simply and reproducibly synthesized at different growth temperature via a one-pot approach, in which N-oleoylmorpholine was used as reaction medium, and cadmium acetate dehydrate and Se powder as precursors. The pure 392 family obtained by surface passivation with either lauric acid or stearic acid at 150 degrees C exhibits strong white-light emission with a maximum quantum yield (QY) up to 27%. The broadband emission (370-680 nm), which is responsible for the white-light, is attributed to photoluminescence from both excitons and surface states. High-quality white-light emission can be stable for a long growth period (about 120 min) and at least a 2-month storage period. The high-resolution transmission electron microscopy (HRTEM) images verify the presence of the small size distribution and good crystallinity of the quantum dots (QDs) with a size range of 1.7-2.0 nm. X-ray diffraction (XRD) and selected area electron diffraction (SAED) confirm that the magic-sized CdSe QDs have a zincblende crystal structure. The energy-dispersed spectrometry (EDS) measurement indicates the as-prepared CdSe QDs have a cadmium-rich surface. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim