The Experts below are selected from a list of 3144 Experts worldwide ranked by ideXlab platform
J Kennedy - One of the best experts on this subject based on the ideXlab platform.
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antiproliferative effects on human lung cell lines a549 activity of Cadmium Selenide nanoparticles extracted from cytotoxic effects investigation of bio electronic application
Materials Science and Engineering: C, 2017Co-Authors: K Kaviyarasu, K Kanimozhi, N Matinise, Maria C Magdalane, Genene Tessema Mola, J KennedyAbstract:Abstract Cadmium Selenide (CdSe) nanoparticles make necessary to acquire more information against the cytotoxic effects on human lung epithelial cells A549 potential adverse to health effects. More biological studies highlighted their cytotoxic potential like pulmonary or respiratory diseases were focused on toxicity nanoparticles mechanisms are involved. The aim of our research, is the comparison of cytotoxicity effect between cells-particle interactions, viability test, membrane integrity and oxidative stress were investigated. XRD showed a strong peak associated with (111) plane of hexagonal CdSe suggesting formation of highly orientated nanoparticles. The longitudinal optical phonon shifted slightly due to strain whereas strong low-energy shoulder shift can be explained within a model for surface optical phonons. Photocatalytic activity of CdSe nanoparticles were investigated by exploiting photocatalytic degradation of Rhodamine B (RhB). The typical UV–vis absorption spectra of RhB solution at different time intervals it can be clearly seen that the relative intensity of the absorption peak corresponding to RhB, with the catalyst for different concentration time intervals (0 mM, 2 mM, 5 mM & 10 mM) of the prepared CdSe nanoparticles. After completion of 5 mM % the dye was completely degraded and the absorption spectra act as a photocatalyst. CdSe nanoparticles exhibits antibacterial activity over a broad range of bacterial species and in particular against P. vulgaris where it out competes four other commonly used S. aureus , E.coli , P. vulgaris and E. hermannii , well as testing four different appropriate concentration from the results showed a significant gain in viable cell numbers of all four bacteria species, with 5 mM and 10 mM being the most effective and 2 mM being the worst, where it provided only a slight improvement from the control in detail.
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antiproliferative effects on human lung cell lines a549 activity of Cadmium Selenide nanoparticles extracted from cytotoxic effects investigation of bio electronic application
Materials Science and Engineering: C, 2017Co-Authors: K Kaviyarasu, K Kanimozhi, N Matinise, Maria C Magdalane, Genene Tessema Mola, J KennedyAbstract:Abstract Cadmium Selenide (CdSe) nanoparticles make necessary to acquire more information against the cytotoxic effects on human lung epithelial cells A549 potential adverse to health effects. More biological studies highlighted their cytotoxic potential like pulmonary or respiratory diseases were focused on toxicity nanoparticles mechanisms are involved. The aim of our research, is the comparison of cytotoxicity effect between cells-particle interactions, viability test, membrane integrity and oxidative stress were investigated. XRD showed a strong peak associated with (111) plane of hexagonal CdSe suggesting formation of highly orientated nanoparticles. The longitudinal optical phonon shifted slightly due to strain whereas strong low-energy shoulder shift can be explained within a model for surface optical phonons. Photocatalytic activity of CdSe nanoparticles were investigated by exploiting photocatalytic degradation of Rhodamine B (RhB). The typical UV–vis absorption spectra of RhB solution at different time intervals it can be clearly seen that the relative intensity of the absorption peak corresponding to RhB, with the catalyst for different concentration time intervals (0 mM, 2 mM, 5 mM & 10 mM) of the prepared CdSe nanoparticles. After completion of 5 mM % the dye was completely degraded and the absorption spectra act as a photocatalyst. CdSe nanoparticles exhibits antibacterial activity over a broad range of bacterial species and in particular against P. vulgaris where it out competes four other commonly used S. aureus , E.coli , P. vulgaris and E. hermannii , well as testing four different appropriate concentration from the results showed a significant gain in viable cell numbers of all four bacteria species, with 5 mM and 10 mM being the most effective and 2 mM being the worst, where it provided only a slight improvement from the control in detail.
A P Alivisatos - One of the best experts on this subject based on the ideXlab platform.
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charge separation and transport in conjugated polymer Cadmium Selenide nanocrystal composites studied by photoluminescence quenching and photoconductivity
Synthetic Metals, 1997Co-Authors: Neil C Greenham, Xiaogang Peng, A P AlivisatosAbstract:We study the processes of charge separation and transport in composite materials formed by mixing Cadmium Selenide nanocrystals with the conjugated polymer poly(2-methoxy, 5-(2'-ethyl)-hexyloxy-p-phenylenevinylene) (MEH-PPV). When the surface of the nanocrystals is treated so as to remove the surface ligand, we find that the polymer photoluminescence is quenched, consistent with rapid charge separation at the polymer/nanocrystal interface. Transmission electron microscopy (JEM) of these quantum dot/conjugated polymer composites shows clear evidence for phase segregation, providing a large area of interface for charge separation to occur. Thin-film photovoltaic devices using the composite materials show quantum efficiencies which are significantly improved over those for pure polymer devices, consistent with improved charge separation. At high concentrations of nanocrystals, where both the nanocrystal and polymer components provide continuous pathways to the electrodes, we find short circuit quantum efficiencies of up to 12 %.
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light emitting diodes made from Cadmium Selenide nanocrystals and a semiconducting polymer
Nature, 1994Co-Authors: Vicki L Colvin, M C Schlamp, A P AlivisatosAbstract:ELECTROLUMINESCENT devices have been developed recently that are based on new materials such as porous silicon1 and semiconducting polymers2,3. By taking advantage of developments in the preparation and characterization of direct-gap semiconductor nanocrystals4–6, and of electroluminescent polymers7, we have now constructed a hybrid organic/inorganic electroluminescent device. Light emission arises from the recombination of holes injected into a layer of semiconducting p-paraphenylene vinylene (PPV)8–10 with electrons injected into a multilayer film of Cadmium Selenide nanocrystals. Close matching of the emitting layer of nanocrystals with the work function of the metal contact leads to an operating voltage11 of only 4V. At low voltages emission from the CdSe layer occurs. Because of the quantum size effect19–24 the colour of this emission can be varied from red to yellow by changing the nanocrystal size. At higher voltages green emission from the polymer layer predominates. Thus this device has a degree of voltage tunability of colour.
K Kaviyarasu - One of the best experts on this subject based on the ideXlab platform.
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antiproliferative effects on human lung cell lines a549 activity of Cadmium Selenide nanoparticles extracted from cytotoxic effects investigation of bio electronic application
Materials Science and Engineering: C, 2017Co-Authors: K Kaviyarasu, K Kanimozhi, N Matinise, Maria C Magdalane, Genene Tessema Mola, J KennedyAbstract:Abstract Cadmium Selenide (CdSe) nanoparticles make necessary to acquire more information against the cytotoxic effects on human lung epithelial cells A549 potential adverse to health effects. More biological studies highlighted their cytotoxic potential like pulmonary or respiratory diseases were focused on toxicity nanoparticles mechanisms are involved. The aim of our research, is the comparison of cytotoxicity effect between cells-particle interactions, viability test, membrane integrity and oxidative stress were investigated. XRD showed a strong peak associated with (111) plane of hexagonal CdSe suggesting formation of highly orientated nanoparticles. The longitudinal optical phonon shifted slightly due to strain whereas strong low-energy shoulder shift can be explained within a model for surface optical phonons. Photocatalytic activity of CdSe nanoparticles were investigated by exploiting photocatalytic degradation of Rhodamine B (RhB). The typical UV–vis absorption spectra of RhB solution at different time intervals it can be clearly seen that the relative intensity of the absorption peak corresponding to RhB, with the catalyst for different concentration time intervals (0 mM, 2 mM, 5 mM & 10 mM) of the prepared CdSe nanoparticles. After completion of 5 mM % the dye was completely degraded and the absorption spectra act as a photocatalyst. CdSe nanoparticles exhibits antibacterial activity over a broad range of bacterial species and in particular against P. vulgaris where it out competes four other commonly used S. aureus , E.coli , P. vulgaris and E. hermannii , well as testing four different appropriate concentration from the results showed a significant gain in viable cell numbers of all four bacteria species, with 5 mM and 10 mM being the most effective and 2 mM being the worst, where it provided only a slight improvement from the control in detail.
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antiproliferative effects on human lung cell lines a549 activity of Cadmium Selenide nanoparticles extracted from cytotoxic effects investigation of bio electronic application
Materials Science and Engineering: C, 2017Co-Authors: K Kaviyarasu, K Kanimozhi, N Matinise, Maria C Magdalane, Genene Tessema Mola, J KennedyAbstract:Abstract Cadmium Selenide (CdSe) nanoparticles make necessary to acquire more information against the cytotoxic effects on human lung epithelial cells A549 potential adverse to health effects. More biological studies highlighted their cytotoxic potential like pulmonary or respiratory diseases were focused on toxicity nanoparticles mechanisms are involved. The aim of our research, is the comparison of cytotoxicity effect between cells-particle interactions, viability test, membrane integrity and oxidative stress were investigated. XRD showed a strong peak associated with (111) plane of hexagonal CdSe suggesting formation of highly orientated nanoparticles. The longitudinal optical phonon shifted slightly due to strain whereas strong low-energy shoulder shift can be explained within a model for surface optical phonons. Photocatalytic activity of CdSe nanoparticles were investigated by exploiting photocatalytic degradation of Rhodamine B (RhB). The typical UV–vis absorption spectra of RhB solution at different time intervals it can be clearly seen that the relative intensity of the absorption peak corresponding to RhB, with the catalyst for different concentration time intervals (0 mM, 2 mM, 5 mM & 10 mM) of the prepared CdSe nanoparticles. After completion of 5 mM % the dye was completely degraded and the absorption spectra act as a photocatalyst. CdSe nanoparticles exhibits antibacterial activity over a broad range of bacterial species and in particular against P. vulgaris where it out competes four other commonly used S. aureus , E.coli , P. vulgaris and E. hermannii , well as testing four different appropriate concentration from the results showed a significant gain in viable cell numbers of all four bacteria species, with 5 mM and 10 mM being the most effective and 2 mM being the worst, where it provided only a slight improvement from the control in detail.
Neil C Greenham - One of the best experts on this subject based on the ideXlab platform.
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ultrafast charge and energy transfer dynamics in conjugated polymer Cadmium Selenide nanocrystal blends
ACS Nano, 2014Co-Authors: Frederik S F Morgenstern, Akshay Rao, Marcus L Bohm, Rene J P Kist, Yana Vaynzof, Neil C GreenhamAbstract:Hybrid nanocrystal-polymer systems are promising candidates for photovoltaic applications, but the processes controlling charge generation are poorly understood. Here, we disentangle the energy- and charge-transfer processes occurring in a model system based on blends of Cadmium Selenide nanocrystals (CdSe-NC) with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) using a combination of time-resolved absorption and luminescence measurements. The use of different capping ligands (n-butylamine, oleic acid) as well as thermal annealing allows tuning of the polymer-nanocrystal interaction. We demonstrate that energy transfer from MDMO-PPV to CdSe-NCs is the dominant exciton quenching mechanism in nonannealed blends and occurs on ultrafast time scales (<1 ps). Upon thermal annealing electron transfer becomes competitive with energy transfer, with a transfer rate of 800 fs independent of the choice of the ligand. Interestingly, we find hole transfer to be much less efficient than electron transfer and to extend over several nanoseconds. Our results emphasize the importance of tuning the organic-nanocrystal interaction to achieve efficient charge separation and highlight the unfavorable hole-transfer dynamics in these blends.
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charge separation and transport in conjugated polymer Cadmium Selenide nanocrystal composites studied by photoluminescence quenching and photoconductivity
Synthetic Metals, 1997Co-Authors: Neil C Greenham, Xiaogang Peng, A P AlivisatosAbstract:We study the processes of charge separation and transport in composite materials formed by mixing Cadmium Selenide nanocrystals with the conjugated polymer poly(2-methoxy, 5-(2'-ethyl)-hexyloxy-p-phenylenevinylene) (MEH-PPV). When the surface of the nanocrystals is treated so as to remove the surface ligand, we find that the polymer photoluminescence is quenched, consistent with rapid charge separation at the polymer/nanocrystal interface. Transmission electron microscopy (JEM) of these quantum dot/conjugated polymer composites shows clear evidence for phase segregation, providing a large area of interface for charge separation to occur. Thin-film photovoltaic devices using the composite materials show quantum efficiencies which are significantly improved over those for pure polymer devices, consistent with improved charge separation. At high concentrations of nanocrystals, where both the nanocrystal and polymer components provide continuous pathways to the electrodes, we find short circuit quantum efficiencies of up to 12 %.
Sandra J Rosenthal - One of the best experts on this subject based on the ideXlab platform.
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pinned emission from ultrasmall Cadmium Selenide nanocrystals
Journal of Chemical Physics, 2008Co-Authors: Albert D Dukes, James R Mcbride, Michael A Schreuder, Jessica A Sammons, Nathanael J Smith, Sandra J RosenthalAbstract:We report pinning of the emission spectrum in ultrasmall CdSe nanocrystals with a diameter of 1.7 nm and smaller. It was observed that the first emission feature ceased to blueshift once the band edge absorption reached 420 nm, though the band edge absorption continued to blueshift with decreasing nanocrystal diameter.
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white light emission from magic sized Cadmium Selenide nanocrystals
Journal of the American Chemical Society, 2005Co-Authors: Michael J Bowers, James R Mcbride, Sandra J RosenthalAbstract:Magic-sized Cadmium Selenide (CdSe) nanocrystals have been pyrolytically synthesized. These ultra-small nanocrystals exhibit broadband emission (420−710 nm) that covers most of the visible spectrum while not suffering from self absorption. This behavior is a direct result of the extremely narrow size distribution and unusually large Stokes shift (40−50 nm). The intrinsic properties of these ultra-small nanocrystals make them an ideal material for applications in solid state lighting and also the perfect platform to study the molecule-to-nanocrystal transition.
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novel polyethylene glycol derivatives of melatonin and serotonin ligands for conjugation to fluorescent Cadmium Selenide zinc sulfide core shell nanocrystals
Journal of Chemical Research-s, 2002Co-Authors: Ian D Tomlinson, Tadd C Kippeny, Laura A Swafford, Nasir H Siddiqui, Sandra J RosenthalAbstract:This paper describes the synthesis and characterisation of derivatives of melatonin and serotonin that may be attached to highly fluorescent Cadmium Selenide/zinc sulfide core shells nanocrystals for use in biological assays and fluorescence imaging applications.
