CdS magic-size clusters exhibiting one sharp ultraviolet absorption singlet peaking at 361 nm

Tang, Junbin; Hui, Juan; Zhang, Meng; Fan, Hongsong; Rowell, N. L.; Huang, Wen; Jiang, Yingnan; Chen, Xiaoqin; Yu, Kui

doi:10.1007/s12274-019-2386-8

Cited by 11 publications

(18 citation statements)

References 52 publications

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“…Although the conventional characterization tools have some shortcomings with regard to providing precise structural and compositional information of colloidal semiconductor small-size QDs and MSCs 20 , 25 – 28 , Supplementary Fig. 4 suggests that the aqueous-phase CdS MSCs are spherical with a diameter smaller than 3 nm, and have a similar structure as that of organic-phase CdS MSC-361 42 , with the ligand to inorganic core weight ratio of 20 to 80 (Supplementary Note 1 ). The Fourier transform infrared (FT-IR) spectrum of the purified CdS MSC-360 sample (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Room-temperature formation of CdS magic-size clusters in aqueous solutions assisted by primary amines

et al. 2020

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Aqueous-phase approaches to semiconductor CdS magic-size clusters (MSCs) and the formation pathway have remained relatively unexplored. Here, we report the demonstration of an aqueous-phase, room-temperature approach to CdS MSCs, together with an exploration of their evolution pathway. The resulting CdS MSCs display a sharp optical absorption peak at about 360 nm and are labeled MSC-360. With CdCl 2 and thiourea as the respective Cd and S sources, and 3-mercarpotopropionic acid as the ligand, CdS MSC-360 develops in a mixture of a primary amine and water. We argue that the primary amine facilitates roomtemperature decomposition of thiourea when CdCl 2 is present, and the formation pathway of MSCs is similar to that in organic-phase approaches. Our findings show there is a viable avenue to room-temperature aqueous-phase formation of CdS MSCs. Providing explanations of the procedure developed including the formation of large aggregates, the present study represents an important advance towards a mechanistic understanding of nanocrystal synthesis.

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Section: Resultsmentioning

confidence: 99%

Room-temperature formation of CdS magic-size clusters in aqueous solutions assisted by primary amines

et al. 2020

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“…1 The collective effort on the synthesis and formation pathway has been moving the field of colloidal semiconductor clusters and nanocrystals one-step forward to transform from an empirical art to science, similar to the advance of organic chemistry. [26][27][28][29][30][31][32][33][34][35][36][37] ASSOCIATED CONTENT…”

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confidence: 99%

One-Step Approach to Single-Ensemble CdS Magic-Size Clusters with Enhanced Production Yields

Zhang

Rowell

et al. 2019

J. Phys. Chem. Lett.

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We report on the development of a single-step method to synthesize colloidal semiconductor magic-size clusters (MSCs) with an enhanced particle yield in a singleensemble form and free of the coproduction of conventional quantum dots (QDs). The present process eliminates the need for the second step of a lower-temperature incubation used in a two-step approach reported recently for the fabrication of single-ensemble MSCs without the contamination of QDs. We demonstrate that the combined use of a secondary phosphine (HPR 2) and an methyl carboxylic acid (RCH(CH 3)COOH, MA) promotes the yield of MSCs and suppresses the nucleation and growth of QDs. With CdO and elemental S powder as Cd and S sources, respectively, single-ensemble of CdS MSC-311 (displaying sharp absorption peaking at 311 nm) evolves directly in a reaction in 1-octadecene with enhanced production yield. The present study introduces a one-step avenue to synthesize effectively and selectively single-ensemble MSCs, and brings further understanding for the twopathway model proposed for the prenucleation stage of QDs.

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“…Diffuse scattering is an important method to get reliable real-space structural information of clusters through the pair distribution function (PDF), which is closely related to the histogram of interatomic distances. ,− The structure Cd 37 S 20 , obtained by replacing In and P atoms in the In 37 P 20 single-crystal model with Cd and S atoms, respectively, was proposed to be a reliable structure model for CdS MSC-311 ,, through previous PDF work. , In recent work, the calculated absorption spectrum of Cd 37 S 20 (InP model) exhibited a peak at 313 nm, the peak position is close to that of CdS MSC-311. Thus, the structure of Cd 37 S 20 is acceptable for the study of CdS MSC-311.…”

Section: Methodsmentioning

confidence: 99%

“…The size mentioned here is proposed to be the size of all three dimensions, including the effect of shape and volume . Abundant explorations have been focused on the shape-dependent optical properties for semiconductor nanoparticles, like CdSe, CdTe, CdS, and PbS with dotted, rod, and wired structures. − In recent years, several types of group II–VI magic-size clusters (MSCs) have been observed in experiments. − MSCs are a kind of special clusters with a defined number of atoms and chemical structures, together with high stability and special optical properties . When MSCs are synthesized experimentally, sharp absorption peaks can be detected, with fixed positions in the UV–vis absorption spectra.…”

Section: Introductionmentioning

confidence: 99%

“…When MSCs are synthesized experimentally, sharp absorption peaks can be detected, with fixed positions in the UV–vis absorption spectra. CdTe MSCs with singlet or doublet absorption features have been found, such as singlet MSC-371 (denoted as sMSC-371), sMSC-448, doublet MSC-371 (denoted as dMSC-371), and dMSC-488. − The words “singlet” and “doublet” refer to absorption features here and have been used to describe the shape of the absorption peak in many works. ,− , CdTe sMSC-371 and dMSC-371, which exhibit diverse absorption features but the same first absorption peak position, have attracted our attention. Although the transmission electron microscopy images of dMSC-371 and sMSC-371 have been reported experimentally, , their detailed atomic structures have not been pointed out.…”

Section: Introductionmentioning

confidence: 99%

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Absorption Features of CdTe Nanoclusters: Aspect Ratio Dependency of the Singlet/Doublet from First-Principles Calculations

et al. 2021

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Two categories of absorption features, singlet and doublet, have been observed in semiconductive II–VI magic-size clusters (MSCs) experimentally; however, the underlying mechanism resulting in the two absorption features has seldom been addressed. Here, the relationship between morphology and absorption features is studied in CdTe nanoclusters using first-principles calculations. The explorations focus on CdTe isomers and nonisomers at first to simulate the isomerization and layer growth pattern in MSCs. Similar conclusions are reached that the absorption spectra exhibit a gradual transition from singlet to doublet as the aspect ratios increase. We further suppose that the shape of CdTe dMSC-371 may be that of sMSC-371 being stretched in one dimension. Density functional theory absorption spectra show significant agreement with the predicted spectra from the Mie–Gans theory, which indicates that the shape of clusters affects the dielectric function directly and results in different absorption features. The major transition orbitals of these optical excitations are assigned by transition dipole moment, oscillator strengths, and density of states. Furthermore, the aspect-ratio-dependent singlet and doublet absorption features are found to be independent of the structural types, including the zinc blende, hollow nanotubes, and hexagonal wurtzite structures. The present study reveals the aspect-ratio-determined absorption behaviors of II–VI MSCs and provides a promising method for predicting the morphology of MSCs with absorption spectroscopy.

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CdS magic-size clusters exhibiting one sharp ultraviolet absorption singlet peaking at 361 nm

Cited by 11 publications

References 52 publications

Room-temperature formation of CdS magic-size clusters in aqueous solutions assisted by primary amines

Room-temperature formation of CdS magic-size clusters in aqueous solutions assisted by primary amines

One-Step Approach to Single-Ensemble CdS Magic-Size Clusters with Enhanced Production Yields

Absorption Features of CdTe Nanoclusters: Aspect Ratio Dependency of the Singlet/Doublet from First-Principles Calculations

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