We synthesized CdSe/CdS giant-shell nanocrystals, with a CdSe core diameter between 2.8 nm and 5.5 nm, and a CdS shell thickness of up to 7-8 nm (equivalent to about 20 monolayers of CdS). Both the core and shell have a wurtzite crystal structure, yielding epitaxial growth of the shell and nearly defect-free crystals. As a result, the photoluminescence (PL) quantum efficiency (QE) is as high as 90%. Quantitative PL measurements at various excitation wavelengths allow us to separate the nonradiative decay into contributions from interface and surface trapping, giving us pathways for future optimization of the structure. In addition, the NCs do not blink, and the giant shell and concurring strong electron delocalization efficiently suppress Auger recombination, yielding a biexciton lifetime of about 15 ns. The corresponding biexciton PL QE equals 11% in 5.5/18.1 nm CdSe/CdS. Variable-temperature time-resolved PL and PL under magnetic fields further reveal that the emission at cryogenic temperature originates from a negative trion-state, in agreement with other CdSe/CdS giant-shell systems reported in the literature. This journal is © the Partner Organisations 2014.
Christodoulou, S., Vaccaro, G., Pinchetti, V., De Donato, F., Grim, J., Casu, A., et al. (2014). Synthesis of highly luminescent wurtzite CdSe/CdS giant-shell nanocrystals using a fast continuous injection route. JOURNAL OF MATERIALS CHEMISTRY. C, 2(17), 3439-3447 [10.1039/c4tc00280f].
Citazione: | Christodoulou, S., Vaccaro, G., Pinchetti, V., De Donato, F., Grim, J., Casu, A., et al. (2014). Synthesis of highly luminescent wurtzite CdSe/CdS giant-shell nanocrystals using a fast continuous injection route. JOURNAL OF MATERIALS CHEMISTRY. C, 2(17), 3439-3447 [10.1039/c4tc00280f]. | |
Tipo: | Articolo in rivista - Articolo scientifico | |
Carattere della pubblicazione: | Scientifica | |
Presenza di un coautore afferente ad Istituzioni straniere: | No | |
Titolo: | Synthesis of highly luminescent wurtzite CdSe/CdS giant-shell nanocrystals using a fast continuous injection route | |
Autori: | Christodoulou, S; Vaccaro, G; Pinchetti, V; De Donato, F; Grim, J; Casu, A; Genovese, A; Vicidomini, G; Diaspro, A; Brovelli, S; Manna, L; Moreels, I | |
Autori: | VACCARO, GIANFRANCO (Secondo) | |
Data di pubblicazione: | 2014 | |
Lingua: | English | |
Rivista: | JOURNAL OF MATERIALS CHEMISTRY. C | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1039/c4tc00280f | |
Appare nelle tipologie: | 01 - Articolo su rivista |