Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation

Singh, Suman; Garg, Sourav; Chahal, Jitender; Raheja, Khushboo; Singh, Deepak P.; Singla, Madan Lal

doi:10.1088/0957-4484/24/11/115602

Cited by 24 publications

(23 citation statements)

References 35 publications

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“…Fluorescence studies (figure 3b, blue trace) revealed that the sharp band edge lies in the visible region at approximately 583 nm (2.1 eV). Typically, the CdS QDs show strong photoluminescence (PL) in the range of 1.6-2.5 eV with the maximum at 2.1 eV closer to near visible region, indicating that PL originates from the recombination of the caged charge carriers (electron and holes) in deep traps introduced by surface states, which is a common feature of cadmium chalcogenides [15].…”

Section: Results and Discussion (A) Characterization Of Cadmium Sulfimentioning

confidence: 99%

Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches

Javed¹,

Fatima²,

Akhter³

et al. 2016

Proc. R. Soc. A.

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We have investigated the attachment of azobenzene photochromic switches on the modified surface of cadmium sulfide (CdS) quantum dots (QDs). The modification of CdS QDs is done by varying the concentration of the capping agent (mercaptoacetic acid) and NH 3 in order to control the size of the QDs. The X-ray diffraction studies revealed that the crystallite size of CdS QDs ranged from 6 to 10 nm. The azobenzene photochromic derivatives bis(4-hydroxybenzene-1-azo)4,4 (1,1 diphenylmethane) (I) and 4,4 -diazenyldibenzoic acid (II) were synthesized and attached with surface-modified CdS QDs to make fluorophore-photochrome CdS-(I) and CdS-(II) dyad assemblies. Upon UV irradiation, the photochromic compounds (I) and (II) undergo a reversible trans-cis isomerization. The photo-induced trans-cis transformation helps to transfer photoexcited electrons from the conduction band of the CdS QDs to the lowest unoccupied molecular orbital of cis isomer of photochromic compounds (I) and (II). As a result, the fluorescence of CdS-(I) and CdS-(II) dyads is suppressed approximately five times compared to bare CdS QDs. The fluorescence modulation in such systems could help to design luminescent probes for bioimaging applications.

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Section: Results and Discussion (A) Characterization Of Cadmium Sulfimentioning

confidence: 99%

Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches

Javed¹,

Fatima²,

Akhter³

et al. 2016

Proc. R. Soc. A.

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“…It is also reported that thioglycolic acid capped CdS particles with a diameter of 3.0-4.0 nm are found to display an emission peak at 530 nm. 46 In the J-aggregate/CdS nanohybrids, however, no photoluminescence emission of CdS nanocrystals is detected, as shown in Fig. 5b.…”

Section: Resultsmentioning

confidence: 89%

In situ synthesis of semiconductor nanocrystals at the surface of tubular J-aggregates

et al. 2014

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Hybrid nanostructures consisting of dye molecules and semiconducting nanocrystals are currently much investigated because they can benefit from the strong absorption of organic dyes and the chemical stability of inorganic components, a combination of properties that is promising for various optoelectronic applications. Here, we report an in situ synthesis method to design hybrid nanotubes by growing metal sulfide (MeS) nanocrystals at the surface of tubular J-aggregates of amphiphilic carbocyanine dyes. In this method, metal cations (Me 2+ ¼ Cd 2+ , Zn 2+ , and Ni 2+ ) are enriched at the negatively charged surface of J-aggregates via electrostatic attraction, giving rise to a diffuse Helmholtz layer. Subsequent addition of thioacetamide and ammonium hydroxide leads to the formation of a dense layer of MeS nanocrystals exclusively close to or at the surface of J-aggregates. Typically, a shell of CdS nanocrystals (size $ 3 nm) is formed at the surface of tubular J-aggregates without significantly affecting the aggregate morphology. The crystal structure is analyzed by electron diffraction revealing a sphalerite structure. The coverage of CdS nanocrystals on J-aggregates can be tuned by varying the concentration of the sulphur source. Efficient energy transfer from CdS nanocrystals to J-aggregates results in the quenching of the CdS photoluminescence. Structurally and morphologically similar hybrid systems of tubular J-aggregates and semiconductor nanocrystals (e.g., ZnS and NiS) are synthesized by analog chemical reactions.

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“…References on CdS nanoparticles are provided for interested readers [49,265,306,307,310,[379][380][381][382][383][384][385].…”

Section: Functionalisation Of Transition Metal Sulphides: Case Studiesmentioning

confidence: 99%

Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist

2017

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Abstract:Metal sulphides, and in particular transition metal sulphide colloids, are a broad, versatile and exciting class of inorganic compounds which deserve growing interest and attention ascribable to the functional properties that many of them display. With respect to their oxide homologues, however, they are characterised by noticeably different chemical, structural and hence functional features. Their potential applications span several fields, and in many of the foreseen applications (e.g., in bioimaging and related fields), the achievement of stable colloidal suspensions of metal sulphides is highly desirable or either an unavoidable requirement to be met. To this aim, robust functionalisation strategies should be devised, which however are, with respect to metal or metal oxides colloids, much more challenging. This has to be ascribed, inter alia, also to the still limited knowledge of the sulphides surface chemistry, particularly when comparing it to the better established, though multifaceted, oxide surface chemistry. A ground-breaking endeavour in this field is hence the detailed understanding of the nature of the complex surface chemistry of transition metal sulphides, which ideally requires an integrated experimental and modelling approach. In this review, an overview of the state-of-the-art on the existing examples of functionalisation of transition metal sulphides is provided, also by focusing on selected case studies, exemplifying the manifold nature of this class of binary inorganic compounds.

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Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation

Cited by 24 publications

References 35 publications

Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches

Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches

In situ synthesis of semiconductor nanocrystals at the surface of tubular J-aggregates

Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist

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