title: Thermal activation of non-radiative Auger recombination in charged colloidal nanocrystals.
abstract: Applications of semiconductor nanocrystals such as biomarkers and light-emitting optoelectronic devices require that their fluorescence quantum yield be close to 100%. However, such quantum yields have not been obtained yet, in part, because non-radiative Auger recombination in charged nanocrystals could not be suppressed completely. Here, we synthesize colloidal core/thick-shell CdSe/CdS nanocrystals with 100% quantum yield and completely quenched Auger processes at low temperatures, although the nanocrystals are negatively photocharged. Single particle and ensemble spectroscopy in the temperature range 30-300 K shows that the non-radiative Auger recombination is thermally activated around 200 K. Experimental results are well described by a model suggesting a temperature-dependent delocalization of one of the trion electrons from the CdSe core and enhanced Auger recombination at the abrupt CdS outer surface. These results point to a route for the design of core/shell structures with 100% quantum yield at room temperature.
authors: Laboratoire de Physique et d'Etude des Matériaux, CNRS, ESPCI, 10 rue Vauquelin 75231 Paris, France.
authors: C
authors: C
authors: Javaux
authors: B
authors: B
authors: Mahler
authors: B
authors: B
authors: Dubertret
authors: A
authors: A
authors: Shabaev
authors: A V
authors: AV
authors: Rodina
authors: Al L
authors: AL
authors: Efros
authors: D R
authors: DR
authors: Yakovlev
authors: F
authors: F
authors: Liu
authors: M
authors: M
authors: Bayer
authors: G
authors: G
authors: Camps
authors: L
authors: L
authors: Biadala
authors: S
authors: S
authors: Buil
authors: X
authors: X
authors: Quelin
authors: J-P
authors: JP
authors: Hermier
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D003102:Colloids / Q000138:chemical synthesis / Q000737:chemistry*; D004583:Electrons; D005453:Fluorescence; D010316:Particle Size; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D013499:Surface Properties
chemical_list: D019187:Cadmium Compounds; D003102:Colloids; D018036:Selenium Compounds; D013440:Sulfides; C034939:cadmium sulfide; C058667:cadmium selenide
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