| Download | - View accepted manuscript: CdS Magic-Sized Nanocrystals Exhibiting Bright Bandgap Photoemission via Thermodynamically Driven Formation (PDF, 694 KiB)
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| DOI | Resolve DOI: https://doi.org/10.1021/nn9009455 |
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| Author | Search for: Li, Minjie1; Search for: Ouyang, Jianying1; Search for: Ratcliffe, Christopher I (Chris)1; Search for: Pietri, Laetitia1; Search for: Wu, Xiaohua2; Search for: Leek, Donald M (Don)1; Search for: Moudrakovski, Igor1; Search for: Quan Lin; Search for: Yu, Kui1 |
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| Affiliation | - National Research Council of Canada. NRC Steacie Institute for Molecular Sciences
- National Research Council of Canada. NRC Institute for Microstructural Sciences
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| Format | Text, Article |
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| Subject | CdS; single-sized nanocrystals; magic-sized nanocrystals (MSNs); one-pot noninjection; band gap emission; homogeneous broadening |
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| Abstract | CdS magic-sized nanocrystals (MSNs) exhibiting both band gap absorption and emission at 378 nm with a narrow bandwidth of 9 nm and quantum yield (QY) of 10% (total QY 28%, in hexane) were synthesized via a one-pot noninjection approach. This CdS MSN ensemble is termed as Family 378. It has been acknowledged that magic-sized quantum dots (MSQDs) are single-sized, and only homogeneous broadening contributes to their bandwidth. The synthetic approach developed is ready and highly reproducible. The formation of the CdS MSQDs was carried out at elevated temperatures (such as 90−140 °C) for a few hours in a reaction flask containing bis(trimethylsilyl)sulfide ((TMS)2S) and Cd(OAc)(OA) in situ made from cadmium acetate dihydrate (Cd(OAc)2·2H2O) and oleic acid (OA) in 1-octadecene (ODE). Low OA/Cd and high Cd/S feed molar ratios favor this formation, whose mechanism is proposed to be thermodynamically driven. 13C solid-state cross-polarization magic-angle spinning (CP/MAS) nuclear magnetic resonance (NMR) demonstrates that the capping ligands are firmly attached to the nanocrystal surface via carboxylate groups. With the cross-polarization from 1H of the alkyl chains to surface 113Cd, 113Cd NMR is able to distinguish the surface Cd (471 ppm) bonding to both −COO− and S and the bulk Cd (792 ppm) bonding to S only. DOSY-NMR was used to determine the size of Family 378 (1.9 nm). The present study provides strategies for the rational design of various MSNs. |
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| Publication date | 2009-11-13 |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 16457847 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 514740b3-37e1-4682-b872-f71079c3033b |
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| Record created | 2011-02-09 |
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| Record modified | 2020-04-16 |
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