Synthesis of type-II CdSe(S)/Fe2O3 core/shell quantum dots: the effect of shell on the properties of core/shell quantum dots

Mirnajafizadeh, Fatemeh; Wang, Fan; Reece, Peter J.; Stride, John A.

doi:10.1007/s10853-016-9828-4

Cited by 16 publications

(8 citation statements)

References 25 publications

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“…Similar to previous reports [50,62], HRTEM did not show the existence of the shell due to the small size of nanoparticles and aggregation. The thickness of the shell was estimated by considering that the total volumes of the CdSe and ZnO components are equal, based upon the fact that the XPS data highlights similar elemental compositions, then from the core particle size of 3.0 nm estimated the shell thickness is simply 2rc33-rc, where r c = the core radius = 1.5 nm, giving a shell thickness of ~0.4 nm.…”

Section: Resultssupporting

confidence: 89%

“…However, the toxicity of Cd-based QDs has largely been attributed to the free Cd ions existing in equilibrium with the QDs in solution [13,36,57]. Coating the QD cores with appropriate shell materials may prevent the core from oxidation, thereby reducing the number of free Cd ions released [48,58,59,60,61,62]. In this work, an aqueous hydrothermal method reported by Aldeek and co-workers [50] was used to synthesize CdSe(S) and CdSe(S)/ZnO QDs using optimized experimental parameters, leading to the formation of highly crystalline QDs.…”

Section: Resultsmentioning

confidence: 99%

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Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots

et al. 2019

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Semiconductor nanocrystals or quantum dots (QDs) have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns over the aqueous dispersivity, toxicity to cells, and stability in biological environments may limit the use of QDs in such applications. Here, we report an investigation into the cytotoxicity of aqueously dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells (HCT-116) and a human skin fibroblast cell line (WS1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 µg/mL, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 µg of QDs per mL, with no sign of cell necrosis, confirming the cytotoxicity data.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots

et al. 2019

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“…However, the toxicity of Cd-based QDs has largely been attributed to the free Cd ions existing in equilibrium with the QDs in solution [11,30,49]. Coating the QD cores with appropriate shell materials may prevent the core from oxidation, thereby reducing the number of free Cd ions released [42, [50][51][52][53][54]. In this work, an aqueous hydrothermal method reported by Aldeek and co-workers [44] was used to synthesise CdSe(S) and CdSe(S)/ZnO QDs using optimized experimental parameters, leading to the formation of highly crystalline QDs.…”

Section: Resultsmentioning

confidence: 99%

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible Quantum Dots

Mirnajafizadeh¹,

Ramsey²,

McAlpine³

et al. 2018

Preprint

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Abstract:Semiconductor nanocrystals or quantum dots (QDs), have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns such as the aqueous dispersivity, toxicity to cells and stability in biological environments may limit the use of QDs in bioapplications. Here, we report an investigation into the cytotoxicity of aqueously dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells and a human skin fibroblast cell line (WS-1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells and compared to that of the heat-shock protein (Hsp90) inhibitor, 17-AAG. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 µg/ml, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 µg of QDs per ml, with no sign of cell necrosis, confirming the cytotoxicity data.

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“…The most of as‐synthesized oil soluble type‐II core/shell QDs were transferred to water‐soluble phase to be used in photovoltaics and biological applications. There have been few reports for the synthesis of type‐II QDs in aqueous medium 91–94. However, the PL QY of aqueous medium synthesized QDs is still lower than the PL QY of water‐soluble QDs obtained via phase transfer approach.…”

Section: Synthesis Of Colloidal Core/shell Qdsmentioning

confidence: 98%

Core/Shell Quantum Dots Solar Cells

Selopal

Zhao

Wang

et al. 2020

Adv Funct Materials

129

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Semiconductor nanocrystals, the so-called quantum dots (QDs), exhibit versatile optical and electrical properties. However, QDs possess high density of surface defects/traps due to the high surface-to-volume ratio, which act as nonradiative carrier recombination centers within the QDs, thereby deteriorating the overall solar cell performance. The surface passivation of QDs through the growth of an outer shell of different materials/compositions called "core/shell QDs" has proven to be an effective approach to reduce the surface defects and confinement potential, which can enable the broadening of the absorption spectrum, accelerate the carrier transfer, and reduce exciton recombination loss. Here, the recent research developments in the tailoring of the structure of core/shell QDs to tune exciton dynamics so as to improve solar cell performance are summarized. The role of band alignment of core and shell materials, core size, shell thickness/compositions, and interface engineering of core/thick shell called "giant" QDs on electron-hole spatial separation, carrier transport, and confinement potential, before and after grafting on the carrier scavengers (semiconductor/electrolyte), is described. Then, the solar cell performance based on core/shell QDs is introduced. Finally, an outlook for the rational design of core/shell QDs is provided, which can further promote the development of high-efficiency and stable QD sensitized solar cells.

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Synthesis of type-II CdSe(S)/Fe2O3 core/shell quantum dots: the effect of shell on the properties of core/shell quantum dots

Cited by 16 publications

References 25 publications

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots

Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible Quantum Dots

Core/Shell Quantum Dots Solar Cells

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