Optical properties of CdS and CdS/ZnS quantum dots synthesized by reverse micelle method

Lien, Vu Thi Kim; Ha, Chu Viet; Ha, Le Thanh; Dat, Nguyen Nhu

doi:10.1088/1742-6596/187/1/012028

Cited by 17 publications

(7 citation statements)

References 6 publications

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“…Alternatively, passivation of core QD with another inorganic shell material emerged as a useful method to improve the luminescence intensity as well as resistance to photodegradation and improve colloidal stability. PbX/CdX (X = S, Se, or Te), − CdS/ZnS, CuInS 2 /ZnS, and InP/GaP/ZnS are examples to such core–shell QDs. By passivating trap states and reducing dangling bonds at the core QD surface, such inorganic shells reduce nonradiative events and enhance lifetime and quantum yield of the QD. , Furthermore, the shell acts as a physical barrier between the core QD and the surrounding medium, protecting the core from environmental factors such as oxidation .…”

Section: Introductionmentioning

confidence: 99%

Production of Small, Stable PbS/CdS Quantum Dots via Room Temperature Cation Exchange Followed by a Low Temperature Annealing Processes

et al. 2017

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Here, we discuss a simple low temperature process for the synthesis of small and stable PbS/CdS QDs with emission below 1100 nm. For this, small PbS QDs with emission below 1100 nm synthesized from PbCl 2 in oleylamine with 1-dodecanethiol, as reported by our group recently, were used. A thin CdS shell was grown on PbS at room temperature (RT) via cation exchange (CE), which is a self-limiting process providing about 100 nm blue shift in the emission maxima, hence is quite practical for reaction control and production of predictable particles. RTCE process provides 6−9 times stronger emission than original PbS with better optical stability. Annealing of the PbS/CdS QDs in solid state at mild temperatures (50−100 °C) improves crystallinity of the particles. Final ligand exchange on the annealed PbS/CdS with 1-dodecanethiol (DT) enhances the long-term stability of particles further. The optimum overall process is determined as RTCE followed by annealing at 50 °C for 1 h and finished with ligand exchange with DT. Influence of these processes on QD structure and optical properties were studied as well as stability in chloroform and petroleum products (diesel and gasoline) for possible optical tagging applications of such liquids. Overall, a simple, controllable, and scalable method is developed to produce highly stable, bright, size-tunable PbS/CdS QDs with emission detectable with low cost semiconductor detectors.

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Section: Introductionmentioning

confidence: 99%

Production of Small, Stable PbS/CdS Quantum Dots via Room Temperature Cation Exchange Followed by a Low Temperature Annealing Processes

et al. 2017

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“…Low full width at half maximum (FWHM) of emission peaks ≈34 nm for CdSe and ≈36 nm for CdSe/CdS QDs also suggests that the monodispersity of the QDs was maintained after shelling. The effectiveness of shelling is further confirmed by the absence of emission peak from CdS layer (which emits at lower wavelengths [ 51 ] ).…”

Section: Resultsmentioning

confidence: 99%

Amplified Spontaneous Emission from Optical Fibers Containing Anisotropic Morphology CdSe/CdS Quantum Dots Under Continuous Wave Excitation

Das,

Dhiman,

Umapathy

et al. 2023

Advanced Photonics Research

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Fiber laser field is typically dominated by rare earth ions as gain material in the core of a silica optical waveguide. Due to their specific emission wavelengths, rare‐earth‐doped fiber lasers are available only at few predefined wavelengths. However, quantum dots (QDs) are materials which show tunable emission with change in size and composition. Due to such tunability, QDs seem to be promising candidates for obtaining fiber lasers at a spectrum of wavelengths which is not possible using rare earth ions. To replace rare earth ions with QDs, it is of paramount importance that QDs show signatures of optical gain. Herein, the synthesis of asymmetric pod‐shaped CdSe/CdS QDs is reported, which demonstrate efficient gain on pumping. The intrinsic gain properties of the QDs are evaluated through transient absorption (TA) spectroscopy. Later, the exquisite QDs are used to fabricate specialty fibers from which amplified spontaneous emission (ASE) is obtained using continuous wave laser pump at room temperature. Finally, emission signal stability is checked by studying photobleaching and controlling the concentration of the QDs.

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“…The synthesized QDs were reported to exhibit excellent photostability and size-dependent luminescence. Cadmium sulfide (CdS) and CdS/ZnS semiconductor QDs were synthesized by the reverse micelle method in a study by Lien et al [ 86 ]. Sodium bis (2-ethylhexyl) sulfosuccinate (AOT) was used as a surfactant.…”

Section: Synthesis Of Qdsmentioning

confidence: 99%

Recent Breakthroughs in Using Quantum Dots for Cancer Imaging and Drug Delivery Purposes

Hamidu,

Pitt,

Husseini

2023

Nanomaterials

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Cancer is one of the leading causes of death worldwide. Because each person’s cancer may be unique, diagnosing and treating cancer is challenging. Advances in nanomedicine have made it possible to detect tumors and quickly investigate tumor cells at a cellular level in contrast to prior diagnostic techniques. Quantum dots (QDs) are functional nanoparticles reported to be useful for diagnosis. QDs are semiconducting tiny nanocrystals, 2–10 nm in diameter, with exceptional and useful optoelectronic properties that can be tailored to sensitively report on their environment. This review highlights these exceptional semiconducting QDs and their properties and synthesis methods when used in cancer diagnostics. The conjugation of reporting or binding molecules to the QD surface is discussed. This review summarizes the most recent advances in using QDs for in vitro imaging, in vivo imaging, and targeted drug delivery platforms in cancer applications.

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Optical properties of CdS and CdS/ZnS quantum dots synthesized by reverse micelle method

Cited by 17 publications

References 6 publications

Production of Small, Stable PbS/CdS Quantum Dots via Room Temperature Cation Exchange Followed by a Low Temperature Annealing Processes

Production of Small, Stable PbS/CdS Quantum Dots via Room Temperature Cation Exchange Followed by a Low Temperature Annealing Processes

Amplified Spontaneous Emission from Optical Fibers Containing Anisotropic Morphology CdSe/CdS Quantum Dots Under Continuous Wave Excitation

Recent Breakthroughs in Using Quantum Dots for Cancer Imaging and Drug Delivery Purposes

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