Alkylthiol-Enabled Se Powder Dissolution in Oleylamine at Room Temperature for the Phosphine-Free Synthesis of Copper-Based Quaternary Selenide Nanocrystals

Liu, Yi; Yao, Dong; Shen, Liang; Zhang, Hao; Zhang, Xindong; Yang, Bai

doi:10.1021/ja300064t

Cited by 216 publications

(245 citation statements)

References 39 publications

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“…It was reported that selenium powder can be reduced by thiols which oxidized to disulfide. 74 Indeed GC-MS analysis confirmed the formation of dihexyl-disulfide (m/z = 234) resulting from oxidation of HTs ( Figure S5). A detailed discussion related to GC-MS data and further control experiments are provided in the Supporting Information File.…”

Section: Investigation Of Thementioning

confidence: 78%

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

Dolai¹,

Dutta

Muhoberac³

et al. 2015

Chem. Mater.

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ABSTRACT:We have designed a new non-phosphinated reaction pathway, which includes synthesis of a new, highly reactive Se-bridged organic species (chalcogenide precursor), to produce bright white light-emitting ultrasmall CdSe nanocrystals of high quality under mild reaction conditions. The detailed characterization of structural properties of the selenium precursor through combined 77 Se NMR and laser desorption ionization-mass spectrometry (LDI-MS) provided valuable insights into Se release and delineated the nanocrystal formation mechanism at the molecular level. The 1 H NMR study showed that the rate of disappearance of Se-precursor maintained a single-exponential decay with a rate constant of 2.3 x 10 -4 s -1 at room temperature. Furthermore, the combination of LDI-MS and optical spectroscopy was used for the first time to deconvolute the formation mechanism of our bright white light-emitting nanocrystals, which demonstrated initial formation of a smaller key nanocrystal intermediate (CdSe)19. Application of thermal driving force for destabilization resulted in (CdSe)n nanocrystal generation with n = 29-36 through continuous dissolution and addition of monomer onto existing nanocrystals while maintaining a living-polymerization type growth mode. Importantly, our ultrasmall CdSe nanocrystals displayed an unprecedentedly large fluorescence quantum yield of ~27% for this size regime (<2.0 nm diameter). These mixed oleylamine and cadmium benzoate ligand-coated CdSe nanocrystals showed a fluorescence lifetime of ~90 ns, a significantly large value for such small nanocrystals, which was due to delocalization of the exciton wavefunction into the ligand monolayer. We believe our findings will be relevant to formation of other metal chalcogenide nanocrystals through expansion of the understanding and manipulation of surface ligand chemistry, which together will allow the preparation of "artificial solids" with high charge conductivity and mobility for advanced solid-state device applications.3

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Section: Investigation Of Thementioning

confidence: 78%

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

Dolai¹,

Dutta

Muhoberac³

et al. 2015

Chem. Mater.

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“…[23][24][25][26][27] Therefore, nontoxic, relatively simple, and reproducible approaches for the synthesis of PbSe NCs with controllable size and shape are of great fundamental and technological interest. [25] Herein, we report a new synthetic route for the preparation of high-quality PbSe NCs. In contrast to other PbSe synthetic methods that routinely require TOPO, we have used the more environmentally friendly solvent oleylamine (OLA).…”

Section: Introductionmentioning

confidence: 99%

A Facile Phosphine‐Free Method for Synthesizing PbSe Nanocrystals with Strong Optical Limiting Effects

Wang

Gao

Wang

et al. 2013

Chemistry An Asian Journal

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PbSe semiconductor nanocrystals (NCs) have attracted ever-growing interest owing to both their fundamental physics and potential applications in a diverse range of fields such as optoelectronic devices and nonlinear optics. The current fabrication strategy for colloidal PbSe NCs, however, frequently involves acutely toxic reagents and tedious reaction procedures, and is plagued by products with poorly controlled size and morphology. Herein, we report a facile, low-cost, and phosphine-free method for synthesizing PbSe NCs, which provides highly uniform NCs with tunable mid-IR absorption, and they are promising for bio-related applications. These high quality NCs were obtained by the reaction of elemental Se and PbCl2 in oleylamine as both the ligand and reaction medium. The high flexibility and reproducibility of the method reported in this study allows us to synthesize monodispersed PbSe NCs with well-controlled size and morphology. In addition, these products show strong optical limiting effects, and thus hold potential for developing nonlinear optical devices.

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“…[64][65] A highly reactive Se precursor by dissolving selenium in 1:1 mixture of amine and thiol is used instead of the typically used selenium-oleylamine mixture. 66 For ZnS shelling, a modified literature method was followed. 24 Details of the synthesis procedure are provided in the Experimental Section.…”

mentioning

confidence: 99%

Real-Space Mapping of Surface Trap States in CIGSe Nanocrystals Using 4D Electron Microscopy

et al. 2016

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Surface trap states in copper indium gallium selenide semiconductor nanocrystals (NCs), which serve as undesirable channels for nonradiative carrier recombination, remain a great challenge impeding the development of solar and optoelectronics devices based on these NCs. In order to design efficient passivation techniques to minimize these trap states, a precise knowledge about the charge carrier dynamics on the NCs surface is essential. However, selective mapping of surface traps requires capabilities beyond the reach of conventional laser spectroscopy and static electron microscopy; it can only be accessed by using a one-of-a-kind, second-generation four-dimensional scanning ultrafast electron microscope (4D S-UEM) with subpicosecond temporal and nanometer spatial resolutions. Here, we precisely map the collective surface charge carrier dynamics of copper indium gallium selenide NCs as a function of the surface trap states before and after surface passivation in real space and time using S-UEM. The time-resolved snapshots clearly demonstrate that the density of the trap states is significantly reduced after zinc sulfide (ZnS) shelling. Furthermore, the removal of trap states and elongation of carrier lifetime are confirmed by the increased photocurrent of the self-biased photodetector fabricated using the shelled NCs.

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Alkylthiol-Enabled Se Powder Dissolution in Oleylamine at Room Temperature for the Phosphine-Free Synthesis of Copper-Based Quaternary Selenide Nanocrystals

Cited by 216 publications

References 39 publications

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

A Facile Phosphine‐Free Method for Synthesizing PbSe Nanocrystals with Strong Optical Limiting Effects

Real-Space Mapping of Surface Trap States in CIGSe Nanocrystals Using 4D Electron Microscopy

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