AICHE JOURNAL
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2016
·Vol. 62
·期 8
·2614-2621
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IF 2.98
Luting Ling,Wei Wang,Cai-Feng Wang,Su Chen
The intrinsic low quantum yield (QY) of type II core shell quantum dots (QDs) composes the limitation for these heterostructured nanomaterials to be used in practical application. Herein, magnetic hyperthermia method is employed to intensify reaction process and facilely synthesize CdTe/CdSe heterostructured QDs with improved optical performance for the first time. The QY of the type II QDs is increased to 49% by further growing an inert ZnO layer. The type I interface between CdSe and ZnO helps confine electrons to the inner structure of the QDs, thus improving the QY. The successful preparation and performance enhancement of the CdTe/CdSe type II QDs via magnetic hyperthermia method demonstrate the great potential of this method for the preparation of other materials. Besides, the red-emission QDs are used as conversion materials in white light emitting diodes to reveal their promising application in practical illumination. © 2016 American Institute of Chemical Engineers AIChE J , 62: 2614–2621, 2016
研究领域:
材料科学
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纳米技术
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DOI
高影响因子
LUMINESCENCE
·
2015
·Vol. 30
·期 8
·1375-1379
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IF 1.518
Yilin Wang,Meihua Yu,Kun Yang,Jianping Lu,Linqing Chen
A simple, low-cost and convenient method was developed for the synthesis of highly luminescent CdSe quantum dots (QDs) in an aqueous medium. Compared with previous methods, this synthesis was carried out in one pot using ascorbic acid (C 6 H 8 O 6 ) to replace NaBH 4 or N 2 H 4 · H 2 O as a reductant, and selenium dioxide to replace selenium or its other hazardous, expensive and unstable compounds as a precursor. The mechanism of CdSe QDs formation was elucidated. The influence of various experimental variables, including refluxing time, Cd/MSA and Cd/Se molar ratios, on the luminescent properties of the QDs were systematically investigated. X-Ray powder diffraction and transmission electron microscopy characterization indicated that the QDs had a pure cubic zinc-blended structure with a spherical shape. Copyright © 2015 John Wiley & Sons, Ltd.
研究领域:
材料科学
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化学
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DOI
PubMed
高影响因子
LUMINESCENCE
·
2014
·Vol. 29
·期 7
·818-823
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IF 1.675
Meiting Dong,Jingyi Xu,Shuxian Liu,Ying Zhou,Chaobiao Huang
Here we report a facile one-pot method for the preparation of high-quality CdSe nanocrystals (NCs) in aqueous solution under an air atmosphere. Compared with the traditional use of NaHSe or H 2 Se, the more stable sodium selenite is utilized as the Se source for preparing highly luminescent CdSe nanocrystals. By using mercaptosuccinic acid (MSA) as the capping agent and borate–citrate acid as the buffering solution, CdSe nanocrystals with high quantum yield (up to 70%) have been synthesized conveniently. The influence of different experimental parameters, such as the pH of the precursor solution, the molar ratio of Cd 2+ to Na 2 SeO 3 and Cd 2+ to MSA on the CdSe nanocrystals, has been systematically investigated. The prepared CdSe NCs were spherical with a size of ~ 5 nm. Copyright © 2014 John Wiley & Sons, Ltd.
研究领域:
材料科学
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化学
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PubMed
高影响因子
Nanoscale
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2019
·Vol. 11
·期 19
·9327-9334
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IF 6.97
Xiongbin Wang,Junjie Hao,Jiaji Cheng,Junzi Li,Jun Miao,Ruxue Li,Yiwen Li,Jiagen Li,Yuhui Liu,Xi Zhu,Yanjun Liu,Xiao Wei Sun,Zikang Tang,Marie-Hélène Delville,Tingchao He,Rui Chen
As opposed to traditional photoluminescence and ultra-violet based optical sensing, we present here a sensing system based on resolved optically active polarization with promising applications. It is based on the ultrathin CdSe nanoplatelets (NPLs) when modified with either L or D-cysteine molecules (L/D-cys) as bio-to-nano ligands. The chiral ligand transfers its chiroptical activity to the achiral nanoplatelets with an anisotropy factor of ∼10−4, which unlocks the chiral excitonic transitions and allows lead ion detection with a limit of detection (LOD) as low as 4.9 nM. Simulations and modelling based on time-dependent density functional theory (TD-DFT) reveal the chiral mechanism of L/D-cys capped CdSe NPLs. The presented CD-based sensing system illustrates an alternative possibility of using chiral CdSe NPLs as competitive chiral sensors for heavy metal ion detection.
研究领域:
材料科学
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环境科学
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分析化学
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DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2013
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IF 4.675
Zhizhong Han,Liyuan Wei,Lele Tang,Chongqi Chen,Haibo Pan,Jianzhong Chen
The large bandgap of ZnO limits its application in photovoltaic devices , thus the semiconductor quantum dots (QDs), such as CdSe, is utilized to improve light-harvesting efficiency of solar cells. The CdSe@ZnO flower-rod core–shell nanocable arrays (CSZFRs) are prepared with a simple ion exchange method from aqueous solutions. The optical absorptions of the nanocable arrays can be controllably tuned to cover almost the entire visible spectrum (>750 nm) via quantum dots (QDs) sensitized attributed to the smaller band gap of CdSe. Moreover, a typical type II band alignment enhance the separation of photogenerated charge carriers, and reduce the electron–hole recombination within CSZFRs, demonstrated by the photoluminescence (PL) quenching after the formation of CSZFR hybrid structures. In addition, the CdSe-sensitized ZnO nanostructures demonstrate broad external quantum efficiency (EQE) in the spectrum from 300 to 740 nm. Therefore, the CSZFRs nanocable heterostruture exhibits a photovoltaic performance with a higher open-circuit photovoltage (−0.93 V Ag/AgCl ) and short-circuit photocurrent (1.00 mA cm −2 ).
研究领域:
材料科学
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能源科学
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DOI
高影响因子
RSC Advances
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2015
·Vol. 5
·期 110
·90570-90577
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IF 3.84
Limin Liu,Xianfeng Zhang,Li Ji,Hanwen Li,Huijuan Yu,Fangjie Xu,Jianhua Hu,Dong Yang,Angang Dong
In the surface treatment of colloidal nanocrystals (NCs), S2− ions have been widely employed as metal-free atomic ligands to efficiently replace the original long hydrocarbon ligands. Prior studies exclusively show that S2− ions considerably quench the photoluminescence (PL) of semiconductor NCs (e.g., CdSe and PbS) during ligand exchange. Here we report that the influence of S2− treatment on the luminescent properties of CdSe NCs is highly dependent on the NC size. We observe an unexpected PL brightening phenomenon when small CdSe NCs (<4 nm) are subject to S2− treatment followed by incubation in the presence of air and light irradiation, whereas PL enhancement is not observed in large CdSe NCs (>4 nm) treated under the same conditions. Systematic characterization establishes the evolution of CdSe/CdS core–shell structures in small CdSe NCs arising from anion exchange between Se2− and S2−, which in conjunction with the subsequent incubation process accounts for the PL enhancement. Notably, 2.1 nm CdSe NCs treated with (NH4)2S exhibit a PL quantum yield (QY) as high as ∼40% after 2 days of incubation, which is comparable to that of conventional hydrophobic CdSe/CdS core–shell NCs synthesized at high temperatures. Our studies demonstrate that S2− ions can substantially substitute Se2− in small CdSe NCs in addition to replacing the surface-coating ligands, enabling highly luminescent, hydrophilic CdSe/CdS core–shell NCs at room temperature.
研究领域:
材料科学
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纳米技术
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光学
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DOI
高影响因子
Journal of Materials Chemistry C
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2020
·Vol. 9
·期 2
·555-561
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IF 7.059
Xiao Shao,Yue Wu,Shuang Jiang,Bin Li,Tianyong Zhang,Yong Yan
The chirality of inorganic semiconductor nanocrystals (NCs) was demonstrated to be sensitive to the particle structures and chiral molecules capped on the NC surfaces. In this work, we found the native achiral ligands used for the synthesis of NCs could also influence their circular dichroism (CD) response. With different native ‘growth’ ligands but similar semiconductor cores, the CD spectra of NCs exhibited mirror images by using the same enantiopure cysteine (Cys) ligands, indicating the inversion of NC chirality. In addition, distinct anisotropic dissymmetry factors (g-factor) were observed. With appropriate native ligands, we prepared chiral cysteine stabilized spherical CdSe NCs (quantum dots, QDs) with the highest g-factor ever reported.
研究领域:
材料科学
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化学
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DOI
高影响因子
Materials Science and Engineering B-Advanced Functional Solid-State Materials
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2022
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IF 3.407
Zuchun Wang,Jian Zhang,Xiaodi Ji,Hao Wu,Xiaojin Xu,Jianming Zhan,Hongqi Shi,Wenjuan Liu,Tao Tang
ZnIn 2 S 4 as an energy band narrow photocatalyst has attracted extensive attentions in water remediation, but the fast carrier recombination efficiency hinders its further utilization. An effective strategy is to boost photocarrier separation and enhance photocatalysis performance by building heterojunction. Here, a simple in-situ deposition method is used to create a unique CdSe/ZnIn 2 S 4 heterojunction structure. By varying the CdSe content, CdSe/ZnIn 2 S 4 composites can be synthesized with diffident photocatalytic properties. The optimal photocatalytic efficiency of CdSe/ZnIn 2 S 4 composite is obtained when 1.0 % CdSe addition, while an overdose of CdSe QDs results in a deterioration of photocatalytic efficiency. 93 % tetracycline (TC) degradation could be attained. And the degradation rate is 1.9 and 2.3 times higher than pure ZnIn 2 S 4 and CdSe. In addition, the CdSe/ZnIn 2 S 4 photocatalytic mechanism complies with the Z-Scheme. In the photodegradation process, the superoxide radicals (·O 2 – ) and holes (h + ) are the primary active agents.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
INORGANIC CHEMISTRY
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2019
·
IF 4.85
Xiao Shao,Tianyong Zhang,Bin Li,Minghao Zhou,Xiaoyuan Ma,Jingchao Wang,Shuang Jiang
Ligand-induced chirality in core/shell nanocrystals (NCs) has attracted extensive attention because of many valuable potential applications. However, the cause of chirality especially in semiconductor nanomaterials is still under debate despite the creation of chiral type I core/shell structures. Herein, we synthesized a kind of new Cu2S/CdSe core/shell nanostructure to study the underlying reason. Four samples of Cu2S/CdSe were synthesized utilizing successive ion layer adsorption and reaction to vary the thickness of the CdSe shell upon a Cu2S core with 5 nm diameter. The chirality of type II Cu2S/CdSe NCs is imparted by l-/d-cysteine and penicillamine, which could be modulated with an increasing thickness of the CdSe shell. To the best of our knowledge, this is the first report of chiral type II core/shell semiconductor NCs. The hybridization theory can explain the variation trend of g factors with every increase in shell thickness from four monolayers (4 ML) to 7 ML. The results indicate that the chiroptical activity of semiconductor NCs is mainly due to hybridization between the holes in the valence band of NCs and the highest occupied molecular orbitals of the chiral ligands. In addition, Cu2S/CdSe NCs show a better chiroptical intensity in comparison with the type I structure according to previous work. The first design of chiral type II Cu2S/CdSe core/shell NCs and a detailed investigation of chiral variation trend help to give a better understanding of the chiral interaction between ligands and core/shell semiconductor nanostructures.
研究领域:
纳米材料科学
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光学
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材料化学
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DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Jiaoyi Shi,Limin Liu,Fangjie Xu,Yi Zhang
Semiconductor nanowires are the ideal building blocks to construct various thin-film electronic and optoelectronic devices, the performance of which is largely determined by their ensemble geometry and surface chemistry in addition to the chemical composition. Here, we report the large-scale and oriented assembly of CdSe nanowires on the basis of a light-induced assembly approach under an external electric field. To further increase the electrical conductivity of nanowire films, the original surface-capping organic ligands are exchanged with small ionic species through a solid-state ligand-exchange process. The resulting surface-modified CdSe nanowire films exhibit markedly enhanced photoresponse properties including high on/off ratios and fast response. This work establishes a simple yet scalable method to fabricate aligned nanowire films with a desired surface chemistry, which can be broadly used in various electronic and optoelectronic devices.
研究领域:
材料科学
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纳米技术
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半导体物理
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 48
·21112-21118
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IF 3.288
Yangen Xie,Chunsheng Wang,Zhijie Yang,Huiying Wei,Jingjing Wei
Self-assembly of inorganic nanocrystals into ordered superlattices is of particular importance for their application in biomedicine and solid-state optoelectronic devices. However, dimensionality-controlled self-assembly of nanocrystals is still in its infancy. Emulsion-droplet confined self-assembly could offer a solution considering that the liquid/liquid interface and inner compartments can be respectively used as 2D and 3D templates for the assembly of nanocrystals, producing assemblies with a controlled dimensionality. CdSe nanorods with different aspect ratios were synthesized, and were applied as building blocks to uncover their assembly modes within the o/w emulsion droplets. The results reveal that by using both hydrophilic and lipophilic surfactants, hydrophobic CdSe nanorods can be locked at the liquid/liquid interface to produce a 2D supracrystalline sheet. In contrast, hydrophilic surfactants alone can result in the formation of 3D supracrystalline spherical colloids in similar conditions. Lipophilic surfactants, such as octylamine, can interact with the alkyl chains coated on the CdSe nanorods strongly, which consequently modulates the assembly mode of nanorods within the emulsion droplets. By considering the soft coatings of these supracrystalline structures with two different dimensionalities, these materials could be ideal candidates for the study of their interactions with biological soft matter.
研究领域:
材料科学
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纳米技术
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生物医学工程
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
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IF 2.76
Ying Zhang,Xiaobo Nie
We introduce a facile way to synthesize high-quality CdSe quantum dots (QDs) in a high-boiling two-phase liquid/liquid system. The cadmium myristic acid salt (Cd-MA) dispersed in the dimethylbenzene and selenourea dissolved in the ethylene glycol (EG) reacted at the two-phase interface for the nucleation and growth of nanocrystals. The n -trioctylphosphine oxide (TOPO) was used as capping agent of the CdSe QDs. In this route, the selenourea used as the precursor was dissolved in viscous ethylene glycol (EG), which facilitated the control of the nanocrystal growth by virtue of the slow decomposition and diffusion of selenourea in EG. The size, shape, crystalline structure and optical properties of CdSe QDs were investigated by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV⿿vis spectrometer and photoluminescence spectroscopy. This route could be exploited to synthesize nanocrystals with a large scale and could broaden to synthesis of metal or other semiconductor nanocrystals.
研究领域:
材料科学
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化学
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DOI
高影响因子
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