Fluorescence quenching caused by aggregation of water-soluble CdSe quantum dots

Noh, Maengseok; Kim, Tae-Hoon; Lee, Hosub; Kim, Chang Koo; Joo, Sang Woo; Lee, Kangtaek

doi:10.1016/j.colsurfa.2010.01.059

Cited by 209 publications

(130 citation statements)

References 20 publications

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“…Among the II-VI semiconductor materials, CdSe is one of the interesting n-type semiconducting materials with direct band gap of 1.74 eV at 300 K [14]. Fluorescence spectrum of CdSe QDs over the visible region can be tuned by varying the particle size [15].…”

Section: Introductionmentioning

confidence: 99%

Aqueous synthesis and characterization of Ni, Zn co-doped CdSe QDs

Thirugnanam

Govindarajan

2016

Int Nano Lett

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Ni, Zn co-doped CdSe quantum dots (QDs) were synthesized by chemical precipitation method through aqueous route. The prepared QDs were characterized by X-ray diffraction (XRD) technique, UV-Vis absorption spectroscopy, photoluminescence (PL) spectroscopy and high resolution transmission electron microscopy (HRTEM). XRD technique results indicate that the prepared samples have a zinc blende cubic phase. From UV-Vis absorption spectroscopy technique, the prepared samples were blue shifted with respect to their bulk counter part due to quantum confinement effect. Among different doping ratios examined, a maximum PL emission intensity was observed for CdSe:Ni(1 %):Zn(1 %) QDs. HRTEM pictures show that the prepared QDs were in spherical shape.

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Section: Introductionmentioning

confidence: 99%

Aqueous synthesis and characterization of Ni, Zn co-doped CdSe QDs

Thirugnanam

Govindarajan

2016

Int Nano Lett

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“…This can be brought on either by constriction of the electrical double layer in high ionic strength solutions, or bridging between particles by oppositely charged counter ions in solution. [72][73][74] Many unique 'nano' effects are a function of the size and surface area of the ENMs (i.e. fluorescence, surface plasmon resonance), these properties, and thus their use for ENP detection, may be lost upon aggregation.…”

Section: Transformation Of Enmsmentioning

confidence: 99%

Current status and future direction for examining engineered nanoparticles in natural systems

et al. 2014

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Environmental context. The detection and characterisation of engineered nanomaterials in the environment is essential for exposure and risk assessment for this emerging class of materials. However, the ubiquitous presence of naturally occurring nanomaterials presents a unique challenge for the accurate determination of engineered nanomaterials in environmental matrices. New techniques and methodologies are being developed to overcome some of these issues by taking advantage of subtle differences in the elemental and isotopic ratios within these nanomaterials.Abstract. The increasing manufacture and implementation of engineered nanomaterials (ENMs) will continue to lead to the release of these materials into the environment. Reliably assessing the environmental exposure risk of ENMs will depend highly on the ability to quantify and characterise these materials in environmental samples. However, performing these measurements is obstructed by the complexity of environmental sample matrices, physiochemical processes altering the state of the ENM and the high background of naturally occurring nanoparticles (NNPs), which may be similar in size, shape and composition to their engineered analogues. Current analytical techniques can be implemented to overcome some of these obstacles, but the ubiquity of NNPs presents a unique challenge requiring the exploitation of properties that discriminate engineered and natural nanomaterials. To this end, new techniques are being developed that take advantage of the nature of ENMs to discern them from naturally occurring analogues. This paper reviews the current techniques utilised in the detection and characterisation of ENMs in environmental samples as well as discusses promising new approaches to overcome the high backgrounds of NNPs. Despite their occurrence in the atmosphere and soil, this review will be limited to a discussion of aqueous-based samples containing ENMs, as this environment will serve as a principal medium for the environmental dispersion of ENMs.

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“…Their sizes were greater than separate QD particles (about 6 nm), and they lose the ability to produce fluorescence signals (Liu et al 2012). One reason for the formation of large particles could be that a part of the original aqueous QD suspension had started to form aggregates, which has been observed and reported previously (Noh et al 2010). Another reason, which is more likely, is that the high concentration of QD suspension applied to the paper surface for SEM tests had aggregated during the drying process.…”

Section: Sem Characterizationmentioning

confidence: 56%

Surface Modification of Cellulose Paper for Quantum Dot-based Sensing Applications

Guan¹,

Tian²,

Cao³

et al. 2015

BioResources

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Cellulose paper specimens with and without surface modification were compared in order to study their physicochemical compatibility with quantum dots (QDs) for biochemical sensing applications. Silane and chitosan modification methods were applied. The distribution of QDs deposited on untreated paper and papers modified with silane and chitosan were investigated in order to understand the interaction between QDs and fibre. Modified papers were shown to significantly reduce the undesirable redistribution of QDs during paper drying. The retention ability and thermal resistance of QDs to the loss of fluorescence on modified papers were also studied for the purpose of determining the most suitable paper surface modification for developing QD-Paper-based analytical devices (QD-PADs). Furthermore, chitosan-modified paper was used to design QD-PADs to quantify glucose concentration in aqueous samples; the quenching effect of the enzymatic product on the fluorescent emission of QDs was used as the indicator system. The change of fluorescence of QDs was measured by a simple in-house constructed fluorescence imaging system. The detection limit of glucose was 5 mg/dL, which is comparable with other reported paper sensors for detection of glucose.

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Fluorescence quenching caused by aggregation of water-soluble CdSe quantum dots

Cited by 209 publications

References 20 publications

Aqueous synthesis and characterization of Ni, Zn co-doped CdSe QDs

Aqueous synthesis and characterization of Ni, Zn co-doped CdSe QDs

Current status and future direction for examining engineered nanoparticles in natural systems

Surface Modification of Cellulose Paper for Quantum Dot-based Sensing Applications

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