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Articoli di riviste sul tema "Ternary quantum dots":

1

Muñoz, Raybel, Eva M. Santos, Carlos A. Galan-Vidal, Jose M. Miranda, Aroa Lopez-Santamarina e Jose A. Rodriguez. "Ternary Quantum Dots in Chemical Analysis. Synthesis and Detection Mechanisms". Molecules 26, n. 9 (8 maggio 2021): 2764. http://dx.doi.org/10.3390/molecules26092764.

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Ternary quantum dots (QDs) are novel nanomaterials that can be used in chemical analysis due their unique physicochemical and spectroscopic properties. These properties are size-dependent and can be adjusted in the synthetic protocol modifying the reaction medium, time, source of heat, and the ligand used for stabilization. In the last decade, several spectroscopic methods have been developed for the analysis of organic and inorganic analytes in biological, drug, environmental, and food samples, in which different sensing schemes have been applied using ternary quantum dots. This review addresses the different synthetic approaches of ternary quantum dots, the sensing mechanisms involved in the analyte detection, and the predominant areas in which these nanomaterials are used.
2

Glassy, Benjamin A., e Brandi M. Cossairt. "Ternary synthesis of colloidal Zn3P2quantum dots". Chemical Communications 51, n. 25 (2015): 5283–86. http://dx.doi.org/10.1039/c4cc08068h.

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Aladesuyi, Olanrewaju A., Thabang C. Lebepe, Rodney Maluleke e Oluwatobi S. Oluwafemi. "Biological applications of ternary quantum dots: A review". Nanotechnology Reviews 11, n. 1 (1 gennaio 2022): 2304–19. http://dx.doi.org/10.1515/ntrev-2022-0136.

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Abstract Semiconductor nanomaterials, also known as quantum dots (QDs), have gained significant interest due to their outstanding optical properties with potential biological and biomedical applications. However, the presence of heavy toxic metals such as Cd, Pb, and Hg in conventional QDs have been a major challenge in their applications. Therefore, it is imperative to seek a viable alternative that will be non-toxic and have similar optical properties as the conventional QDs. Ternary I–III–VI QDs have been found to be suitable alternatives. Their optical properties are tunable and have emissions in the near-infrared region. These properties make them useful in a wide range of biological applications. Hence, this review focuses on the recent progress in the use of ternary QDs in Forster resonance energy transfer (FRET), nanomedical applications such as drug and gene delivery. It also discusses the biophotonic application of ternary I–III–VI QDs in optical imaging, biosensing, and multimodal imaging. Furthermore, we looked at the pharmacokinetics and biodistribution of these QDs, and their toxicity concerns. Finally, we looked at the current status, challenges, and future directions in the application of these ternary QDs.
4

Hai, Nguyen Ngọc, Nguyen Hai Yen, Duong Thi Giang, Dinh Hung Cuong, Nguyen Duc Nhat, Pham Thu Nga e Dao Tran Cao. "Mechanism to Detect Pesticide Residues in Tealeaves Based on CdZnSe/ZnS Ternary Alloy Quantum Dots". Communications in Physics 25, n. 1 (15 maggio 2015): 67. http://dx.doi.org/10.15625/0868-3166/25/1/5601.

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In this report, we present the optical properties of the biosensors fabricated from CdZnSe/ZnS quantum dots. The optical properties such as absorption and emission of the ternary quantum dots before and after coupling with the protein molecules like streptavidine (SA) and acetylcholinesterase enzymes (AChE), to form a biosensor structure, will be presented. In particular, the changes in luminescence intensity according to the pH value of the solution environment containing biosensor have been considered, before and after the presence of pesticides. The changes in luminescence intensity of the biosensor after the presence of pesticide over time from 2 seconds to 26 minutes were also surveyed. We have been carried out the tests to determine the trace amounts of commercial pesticides like Motox 5EC, containing 5% cypermethrin and Tungatin 10 EC, containing 10% abamectin, on the real samples of tealeaves. Some characteristics of the relationship between composition, structure, and special optical properties of ternary alloy quantum dots will also be presented. These studies open up the potential applications of ternary quantum dots for agricultural production.
5

Jiang, Tianhao, Chaoqun Shang, Qingguo Meng, Mingliang Jin, Hua Liao, Ming Li, Zhihong Chen, Mingzhe Yuan, Xin Wang e Guofu Zhou. "The Ternary Heterostructures of BiOBr/Ultrathin g-C3N4/Black Phosphorous Quantum Dot Composites for Photodegradation of Tetracycline". Polymers 10, n. 10 (9 ottobre 2018): 1118. http://dx.doi.org/10.3390/polym10101118.

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Herein, we synthesized BiOBr/ultrathin g-C3N4/ternary heterostructures modified with black phosphorous quantum dots using a simple water bath heating and sonication method. The ternary heterostructure was then used for the photocatalytic degradation of tetracycline in visible light, with an efficiency as high as 92% after 3 h of irradiation. Thus, the photodegradation efficiency is greatly improved compared to that of ultrathin g-C3N4, BiOBr, and black phosphorous quantum dots alone. The synthesized ternary heterostructure improves the charge separation efficiency, thus increasing the photodegradation efficiency. This work provides a new and efficient method for the degradation of antibiotics in the environment.
6

Sun, Jianhui, Michio Ikezawa, Xiuying Wang, Pengtao Jing, Haibo Li, Jialong Zhao e Yasuaki Masumoto. "Photocarrier recombination dynamics in ternary chalcogenide CuInS2 quantum dots". Physical Chemistry Chemical Physics 17, n. 18 (2015): 11981–89. http://dx.doi.org/10.1039/c5cp00034c.

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Photocarrier recombination dynamics in ternary chalcogenide CuInS2 quantum dots (CIS QDs) was studied by means of femtosecond transient-absorption (TA) and nanosecond time-resolved photoluminescence (PL) spectroscopy.
7

Han, Xu, Sumeet C. Pandey e Dimitrios Maroudas. "Kinetics of interdiffusion in semiconductor ternary quantum dots". Applied Physics Letters 101, n. 14 (ottobre 2012): 141906. http://dx.doi.org/10.1063/1.4757148.

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8

Gelchuk, Y., O. Boreiko, G. Okrepka e Yu Khalavka. "Synthesis and optical properties of AgInS2 nanoparticles". Chernivtsi University Scientific Herald. Chemistry, n. 818 (2019): 12–19. http://dx.doi.org/10.31861/chem-2019-818-02.

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Ternary chalcogenide Ag-In quantum dots (QDs) are more environmentally friendly than known Cd-, Pb- and P-containing nanoparticles. Here we review the literature on colloidal synthesis methods, properties, and promising fields for the application of AgInS2 quantum dots. Similar to the QDs of lead and cadmium chalcogenides, the most accurate control over the structure and morphology of AgInS2 QDs is achieved by using the method of introducing precursors into high-boiling organic solvents. However, to realize the potential applications of ternary quantum dots, in particular as luminescent biomarkers, the quantum dots must be soluble in polar solvents, especially water. The transfer of quantum dots into aqueous solutions is usually accomplished by exchanging primary lyophilic ligands with smaller bifunctional molecules, such as thioglycolic (or mercapto­propionic) acids, which can passivate the surface of the quantum dots while making them soluble in the polar environment. Methods of colloidal synthesis of AgInS2 / ZnS quantum dots can be classified into the following types: Injection of ions into a high-boiling solvent Synthesis in a mixture of solvents Synthesis in the aquatic environment Methods for the synthesis of AgInS2 QDs in both aqueous solution and organic solvent medium are described. Examples of application of quantum dots for biomedical purposes and in photovoltaic and sensory devices are given. Quantum dots have high photostability and brightness, are characterized by a wide range of absorption and narrow spectral bands of radiation, ie meet most of the criteria for fluorescent materials and biosensors for imaging cancer cells in antitumor therapy, immunofluorescent labeling of proteins, detection of toxins s, visualize intracellular structures, etc. Quantum dots of tertiary chalcogenides, in particular CuInS2 and AgInS2, may be an alternative to quantum dots of binary lead and cadmium chalcogenides for use in light-emitting and light-absorbing systems, such as LEDs, sensors and solar absorbers.
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Kurshanov, D. A., I. A. Arefina, M. S. Stepanova, A. Dubavik e A. V. Baranov. "Effect of Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=- nanoparticle concentration on the luminescence of AgInS-=SUB=-2-=/SUB=-/ZnS in hybrid complex CaCO-=SUB=-3-=/SUB=--Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-@AgInS-=SUB=-2-=/SUB=-/ZnS-=SUP=-*-=/SUP=-". Оптика и спектроскопия 129, n. 11 (2021): 1424. http://dx.doi.org/10.21883/os.2021.11.51649.1418-21.

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In this paper, we studied the properties of a multifunctional system, in which the luminescent and magnetic properties are combined. The calcium carbonate microspheres are used as porous matrices for complexes combining luminescence properties of AgInS2/ZnS quantum dots and magnetic properties of Fe3O4 nanoparticles. The study investigates the effect of magnetic nanoparticles concentration on optical properties of quantum dots in CaCO3-Fe3O4@AgInS2/ZnS complexes. It is shown that applying calcium carbonate microspheres as a matrix permits to reduce quenching of the quantum dots luminescence. Keywords: hybrid system; ternary quantum dots; magnetic nanoparticles; iron oxide; calcium carbonate microspheres.
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Kurshanov D.A., Arefina I. A., Stepanova M. S., Dubavik A. e Baranov A. V. "Effect of Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=- nanoparticle concentration on the luminescence of AgInS-=SUB=-2-=/SUB=-/ZnS in hybrid complex CaCO-=SUB=-3-=/SUB=--Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-@AgInS-=SUB=-2-=/SUB=-/ZnS". Optics and Spectroscopy 130, n. 14 (2022): 2134. http://dx.doi.org/10.21883/eos.2022.14.53999.1418-21.

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In this paper, we studied the properties of a multifunctional system, in which the luminescent and magnetic properties are combined. The calcium carbonate microspheres are used as porous matrices for complexes combining luminescence properties of AgInS2/ZnS quantum dots and magnetic properties of Fe3O4 nanoparticles. The study investigates the effect of magnetic nanoparticles concentration on optical properties of quantum dots in CaCO3-Fe3O4@AgInS2/ZnS complexes. It is shown that applying calcium carbonate microspheres as a matrix permits to reduce quenching of the quantum dots luminescence. Keywords: hybrid system; ternary quantum dots, magnetic nanoparticles, iron oxide; calcium carbonate microspheres.

Tesi sul tema "Ternary quantum dots":

1

Ndangili, Peter Munyao. "Electrochemical and optical modulation of selenide and telluride ternary alloy quantum dots genosensors". Thesis, University of the Western Cape, 2012. http://hdl.handle.net/11394/4025.

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Philosophiae Doctor - PhD
Electroanalytical and optical properties of nanoscale materials are very important for biosensing applications as well as for understanding the unique one-dimensional carrier transport mechanism. One-dimensional semiconductor nanomaterials such as semiconductor quantum dots are extremely attractive for designing high-density protein arrays. Because of their high surfaceto-volume ratio, electro-catalytic activity as well as good biocompatibility and novel electron transport properties make them highly attractive materials for ultra-sensitive detection of biological macromolecules via bio-electronic or bio-optic devices. A genosensor or gene based biosensor is an analytical device that employs immobilized deoxyribonucleic acid (DNA) probes as the recognition element and measures specific binding processes such as the formation of deoxyribonucleic acid-deoxyribonucleic acid (DNA-DNA), deoxyribonucleic acid- ribonucleic acid (DNA-RNA) hybrids, or the interactions between proteins or ligand molecules with DNA at the sensor surface.In this thesis, I present four binary and two ternary-electrochemically and optically modulated selenide and telluride quantum dots, all synthesised at room temperature in aqueous media. Cationic gallium (Ga3+) synthesized in form of hydrated gallium perchlorate salt[Ga(ClO4)3.6H2O] from the reaction of hot perchloric acid and gallium metal was used to tailor the optical and electrochemical properties of the selenide and telluride quantum dots. The synthesized cationic gallium also allowed successful synthesis of novel water soluble and biocompatible capped gallium selenide nanocrystals and gallium telluride quantum dots. Cyclic voltammetric studies inferred that presence of gallium in a ZnSe-3MPA quantum dot lattice improved its conductivity and significantly increased the electron transfer rate in ZnTe-3MPA.Utraviolet-visible (UV-vis) studies showed that incorporation of gallium into a ZnSe-3MPA lattice resulted in a blue shift in the absorption edge of ZnSe-3MPA from 350 nm to 325 nm accompanied by decrease in particle size. An amphiphilic bifunctional molecule, 3-Mercaptopropionic acid (3-MPA) was used as a capping agent for all quantum dots. It was found that 3-MPA fully solubilised the quantum dots, made them stable, biocompatible, non agglomerated and improved their electron transfer kinetics when immobilized on gold electrodes.Retention of the capping agent on the quantum dot surface was confirmed by Fourier transform infrared spectroscopy (FTIR) which gave scissor type bending vibrations of C-H groups in the region 1365 cm-1 to 1475 cm-1, stretching vibrations of C=O at 1640 cm-1, symmetric and asymmetric vibrations of the C-H in the region 2850 cm-1 to 3000 cm-1 as well as stretching vibrations of –O-H group at 3435 cm-1. The particle size and level of non-agglomeration of the quantum dots was studied by high resolution transmission electron microscopy (HRTEM). The optical properties of the quantum dots were studied using UV-vis and fluorescence spectroscopic techniques.Quantum dot/nanocrystal modified gold electrodes were prepared by immersing thoroughly cleaned electrodes in the quantum dot/nanocrystal solution, in dark conditions for specific periods of time. The electrochemical properties of the modified electrodes were characterized by cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemical impedance and spectroscopy (EIS). Six sensing platforms were then prepared using quantum dot/nanocrystal, one of which was used for detection of dopamine while the rest were used for detection of a DNA sequence related to 5-enolpyruvylshikimate-3-phosphate synthase, a common vector gene in glyphosate resistant transgenic plants.The first sensing platform, consisting of ZnSe-3MPA modified gold electrode (Au|ZnSe-3MPA) gave rise to a novel method of detecting dopamine in presence of excess uric acid and ascorbic acid. Using a potential window of 0 to 400 mV, the ZnSe-3MPA masked the potential for oxidation of uric and ascorbic acids, allowing detection of dopamine with a detection limit of 2.43 x 10-10 M (for SWV) and 5.65 x 10-10 M (for steady state amperometry), all in presence of excess uric acid (>6500 higher) and ascorbic acid (>16,000 times higher). The detection limit obtained in this sensor was much lower than the concentration of dopamine in human blood(1.31 x 10-9 M), a property that makes this sensor a potential device for detection of levels of dopamine in human blood.The other sensing platforms were prepared by bioconjugation of amine-terminated 20 base oligonucleotide probe DNA (NH2-5′-CCC ACC GGT CCT TCA TGT TC-3′) onto quantum dot modified electrodes with the aid of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). The prepared DNA electrodes were electrostatically hybridized with different sequences which included 5′-GAA CAT GAA GGA CCG GTG GG-3′ (complementary target), 5′-CATAGTTGCAGCTGCCACTG-3′ (non complementary target) and 5′-GATCATGAAGCACCGGAGGG-3′ (3-base mismatched target).The hybridization events were monitored using differential pulse voltammetry (DPV) and SWV by monitoring the guanine oxidation signal or using EIS by monitoring changes in the charge transfer resistance. The quantum dot genosensors were characterized by low detection limits (in the nanomolar range), long linear range (40 - 150 nM) and were able to discriminate among complementary, non-complementary and 3-base mismatched target sequences.
2

Kauffer, Florence-Anaïs. "Synthèse, stabilité et toxicité de quantum dots à coeur CdSe". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0006/document.

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Parce qu'ils présentent des propriétés remarquables par rapport à leurs équivalents massifs, les nanomatériaux occupent une place de plus en plus importante dans l'industrie et en médecine. Leur essor rapide a généré de nombreuses craintes dans l'opinion publique notamment au regard de certaines méconnaissances liées à leur toxicité. Notre projet vise l'utilisation du séléniure de cadmium (CdSe) comme matériau modèle afin d'établir une corrélation entre la structure chimique des nanoparticules, leur réactivité de surface, leur (photo)stabilité et leur toxicité. Des quantum dots (QDs) CdSe et alliages CdSe(S) ont été préparés en milieu aqueux à 100°C ou par voie hydrothermale de manière à ne différer que par leur structure chimique de coeur (alliage ternaire vs semi-conducteur binaire) alors que d'autres paramètres comme la taille, la charge ou la nature du ligand de surface, ont été maintenus constants. Des études de cytotoxicité menées sur Escherichia coli ont montré que la libération de Cd2+ jouait un rôle important dans la toxicité pour les deux QDs. Nos résultats ont également mis en évidence que les QDs CdSe(S) alliés étaient plus stables et moins toxiques que les QDs CdSe. Sans négliger l'importance de la libération d'ion Cd2+ par les nanoparticules, une corrélation entre la stabilité et la production d'espèces réactives de l?oxygène (EROs) a montré que la toxicité était en partie dépendante de la photostabilité des QDs. Notre étude met en perspective une relation entre la réactivité, la stabilité du coeur des nanoparticules, et la toxicité photo-induite
Due to their unique properties compared to their bulk counterparts, nanomaterials have gained considerable attention, especially in industry and medicine. Their fast development has generated many public concerns, especially because of a lack of knowledge regarding their toxicity. Our project aims to use cadmium selenide (CdSe) as a model material in order to initiate a research aiming at establishing a correlation between the nanoparticles chemical structure, their surface reactivity, their stability and their toxicity. CdSe and alloyed CdSe(S) quantum dots (QDs) were prepared in aqueous phase either at 100°C or under hydrothermal conditions in order to differ solely by their core chemical structure (ternary alloy vs binary semiconductor), while other parameters such as the size, the surface charge or the surface ligand, have been kept constant. Cytotoxicity studies carried out on Escherichia coli have shown that release of Cd2+ played a key role in the toxicity for both QDs. However, alloyed CdSe(S) QDs were also found more stable and less toxic than CdSe nanocrystals. Without disregarding the importance of Cd2+ ions release by the nanoparticles, a correlation between the stability and the production of reactive oxygen species (ROS) showed that toxicity was dependent on QDs photostability. Our study highlights a relationship between the core reactivity, stability and the photo-induced toxicity QD nanoparticles
3

Mao, Baodong. "Synthesis and Property Characterization of Novel Ternary Semiconductor Nanomaterials". Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1334065821.

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Raevskaya, Alexandra, Oksana Rozovik, Anastasiya Novikova, Oleksandr Selyshchev, Oleksandr Stroyuk, Volodymyr Dzhagan, Irina Goryacheva, Nikolai Gaponik, Dietrich R. T. Zahn e Alexander Eychmüller. "Luminescence and photoelectrochemical properties of size-selected aqueous copper-doped Ag–In–S quantum dots". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-235077.

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Ternary luminescent copper and silver indium sulfide quantum dots (QDs) can be an attractive alternative to cadmium and lead chalcogenide QDs. The optical properties of Cu–In–S and Ag–In–S (AIS) QDs vary over a broad range depending on the QD composition and size. The implementation of ternary QDs as emitters in bio-sensing applications can be boosted by the development of mild and reproducible syntheses directly in aqueous solutions as well as the methods of shifting the photoluminescence (PL) bands of such QDs as far as possible into the near IR spectral range. In the present work, the copper-doping of aqueous non-stoichiometric AIS QDs was found to result in a red shift of the PL band maximum from around 630 nm to ∼780 nm and PL quenching. The deposition of a ZnS shell results in PL intensity recovery with the highest quantum yield of 15%, with almost not change in the PL band position, opposite to the undoped AIS QDs. Size-selective precipitation using 2-propanol as a non-solvent allows discrimination of up to 9 fractions of Cu-doped AIS/ZnS QDs with the average sizes in the fractions varying from around 3 to 2 nm and smaller and with reasonably the same composition irrespective of the QD size. The decrease of the average QD size results in a blue PL shift yielding a series of bright luminophors with the emission color varies from deep-red to bluish-green and the PL efficiency increases from 11% for the first fraction to up to 58% for the smallest Cu-doped AIS/ZnS QDs. The rate constant of the radiative recombination of the size-selected Cu-doped AIS/ZnS QDs revealed a steady growth with the QD size decrease as a result of the size-dependent enhancement of the spatial exciton confinement. The copper doping was found to result in an enhancement of the photoelectrochemical activity of CAIS/ZnS QDs introduced as spectral sensitizers of mesoporous titania photoanodes of liquid-junction solar cells.
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Mabrouk, Salima. "Synthèse par voie colloïdale et étude des propriétés optiques et structurales de nanocristaux ternaires ZnSeS dopés". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0169.

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Depuis quelques années, les QDs ternaires ont connu un développement exponentiel grâce à leurs propriétés, notamment leur photoluminescence, qui peut non seulement être contrôlée par leur taille mais également par leur composition. Dans le cadre de cette thèse, nous avons développé une nouvelle méthode de synthèse « verte » en milieu aqueux de QDs ternaires ZnSeS dopés et nous avons étudié l'effet de la variation du dopant (Mn2+, Cu2+ou Cu2+/Al3+) ainsi que de sa localisation (dans le cœur ou dans la coquille) sur leurs propriétés optiques et structurales. La première partie de ce travail décrit la synthèse des QDs ternaires cœur ZnSeS:Mn et cœur/coquille ZnSeS:Mn/ZnS en utilisant le 2-MPA comme ligand. Les résultats obtenus montrent que ces nanocristaux peuvent être préparés avec des rendements quantiques de 22 et 41%, respectivement. Ces QDs ont montré une excellente photostabilité sous irradiation UV et peuvent facilement être transférés en phase organique à l'aide du ligand hydrophobe octanethiol et cela sans altération de leurs propriétés optiques. Par la suite, des QDs cœur/coquille/coquille ZnSeS/ZnS:Cu/ZnS pour lesquels le dopant Cu est introduit dans la première coquille ont été préparés en utilisant le 3-MPA comme ligand. Une excellente (photo)stabilité en présence d'air et d'oxygène ont été observés. Les QDs cœur/coquille/coquille ZnSeS/ZnS:Cu/ZnS ont un rendement quantique de photoluminescence de 20% et ont été utilisés comme sondes photoluminescentes pour la détection des ions Pb2+ en milieu aqueux. Une extinction sélective de l'émission de photoluminescence en présence des ions Pb2+ a été observée. Enfin, des QDs co-dopés Cu et Al, ZnSeS/ZnS:Cu/ZnS:Al/ZnS (première coquille dopée avec Cu2+ et deuxième coquille dopée avec Al3+) ont été préparés. Le co-dopage permet l'amélioration des propriétés optiques, notamment du rendement quantique (jusqu'à 32%) ainsi que de la durée de vie de photoluminescence des QDs dopés Cu
In recent years, ternary QDs have experienced an exponential development thanks to their properties, especially their photoluminescence, which can be controlled not only by their size but also by their composition. As part of this thesis, we developed a new "green" synthesis in aqueous media of ZnSeS-doped ternary QDs and we studied the effect of the variation of the dopant (Mn2+, Cu2+, or Cu2+/Al3+) as well as its localization (in the core or in the shell) on their optical and structural properties. The first part of this work describes the synthesis of ZnSeS:Mn ternary QDs and ZnSeS:Mn/ZnS core/shell using 2-MPA as a ligand. The results obtained show that these nanocrystals can be prepared with quantum yields of 22% and 41%, respectively. These QDs have shown excellent photostability under UV irradiation and can easily be transferred to the organic phase using the hydrophobic octanethiol ligand without altering their optical properties. Subsequently, core/shell ZnSeS/ZnS:Cu/ZnS QDs for which the Cu dopant is introduced into the first shell were prepared using 3-MPA as a ligand. Excellent (photo)stability in the presence of air and oxygen was observed. ZnSeS/ZnS:Cu/ZnS core/shell QDs have a 20% photoluminescence quantum yield and have been used as photoluminescent probes for the detection of Pb2+ ions in aqueous media. A selective extinction of the photoluminescence emission in the presence of Pb2+ ions was observed. Finally, Cu and Al co-doped QDs, ZnSeS/ZnS:Cu/ZnS:Al/ZnS (first shell doped with Cu2+ and second shell doped with Al3+) were prepared. Co-doping allows the improvement of the optical properties, including quantum efficiency (up to 32%) as well as the photoluminescence lifetime of Cu-doped QDs
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Widmann, Frédéric. "Epitaxie par jets moléculaires de GaN, AlN, InN et leurs alliages : physique de la croissance et réalisation de nanostructures". Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10234.

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Ce travail a porte sur la croissance epitaxiale des nitrures d'elements iii gan, aln, et inn, en utilisant l'epitaxie par jets moleculaires assistee par plasma d'azote. Nous avons optimise les premiers stades de la croissance de gan ou aln sur substrat al#2o#3 (0001). Le processus utilise consiste a nitrurer la surface du substrat a l'aide du plasma d'azote, afin de la transformer en aln, puis a faire croitre une couche tampon d'aln ou de gan a basse temperature, avant de reprendre la croissance de gan ou aln a haute temperature (680 a 750c). Nous avons en particulier etudie les proprietes d'une couche de gan en fonction de la temperature a laquelle est realisee l'etape de nitruration. Lorsque les conditions de demarrage de la croissance sont optimisees, nous avons pu observer des oscillations de rheed pendant la croissance de la couche de gan. Nous avons etudie l'effet du rapport v/iii sur la morphologie de surface et les proprietes optiques et structurales de cette couche. Nous avons propose l'utilisation de l'indium en tant que surfactant pour ameliorer ces proprietes. Nous avons ensuite aborde la realisation de superreseaux gan/aln dont nous avons optimise les interfaces. Les mecanismes de relaxation des contraintes de aln sur gan et gan sur aln ont ete etudies. Nous avons egalement elabore les alliages algan et ingan, comme barrieres quantiques dans les heterostructures. Nous avons montre que la relaxation elastique des contraintes de gan en epitaxie sur aln donne lieu a la formation d'ilots de tailles nanometriques, qui se comportent comme des boites quantiques. Leur densite et leur taille dependent de la temperature de croissance, et des conditions de murissement apres croissance. Les proprietes optiques de ces ilots sont gouvernees a la fois par les effets de confinement quantique et par le fort champ piezo-electrique induit par la contrainte dans les ilots.
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Gourgon, Cécile. "Fabrication et caractérisation optique de fils et boites quantiques CdTe/CdZnTe". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10145.

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Un certain nombre de techniques ont ete developpees ces dernieres annees pour fabriquer des nanostructures quantiques, principalement dans le domaine des semiconducteurs iii-v. Nous avons realise des fils et des boites quantiques de semiconducteurs ii-vi, a partir de puits quantiques cdte/cdznte, soit par nanolithographie et gravure de structures 2d, soit directement par epitaxie par jets moleculaires avec une croissance en deux etapes. Les proprietes optiques de ces nanostructures ont ete etudiees en photoluminescence a basse temperature (2k). Dans la premiere approche, les nanostructures ont ete obtenues par lithographie electronique et gravure seche. Nous avons developpe une etape de gravure supplementaire consistant en une oxydation anodique de la couche de surface. Cette etape permet de reduire la taille des fils et des boites et d'eliminer la couche de defauts introduite en surface par la premiere gravure. Les etudes optiques ont prouve l'existence de cette couche de defauts d'une epaisseur de 30 nm environ. Elle contient des centres radiatifs qui localisent les excitons et permet d'augmenter le rendement radiatif des structures de largeur superieure a 150 nm. Pour des tailles inferieures, les recombinaisons sur les defauts non radiatifs de surface font chuter l'intensite de luminescence. Pour s'affranchir des problemes dus a la gravure (fluctuations de largeur, defauts non radiatifs), nous avons developpe une autre approche basee sur une croissance epitaxiale directe. Un puits quantique cdte/cdznte est depose sur la face clivee 110 d'un superreseau contraint. Celui-ci induit une modulation de contrainte dans le plan de la recroissance, et donc un confinement lateral dans le puits 110. La luminescence de ces fils quantiques est decalee vers le rouge par rapport a celle du puits 2d. Ce decalage depend de la densite d'excitation, ce qui est explique par le champ piezoelectrique lateral dans les fils
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Yeh, Chun-Hsien, e 葉俊顯. "Fabrication and Characterization of Ternary ZnSTe Quantum Dots". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/20350072991612087287.

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碩士
國立臺灣大學
物理學研究所
87
In this thesis, we present our investigation on the Volmer-Weber mode growth and characterization of ternary ZnSTe/ZnS quantum dots (QDs) have been studied. The ZnSTe quantum dots were grown by MOCVD (Metal-Organic Chemical Vapor Deposition). The basic idea of our deposition method is to embed small island directly in another material with wider band gap. Based on this concept, a rough layer was first prepared as a starting surface. In this study, we choose ZnS was chosen as the rough layer. ZnSTe quantum dots were then grown on this rough surface. After that, the quantum dots were covered by ZnS barrier layer. Dot size can be controlled by growth duration. The obtained samples of the ZnSTe/ZnS QDs were characterized by X-Ray diffraction and the photoluminescence(PL)measurements. In the X-Ray diffraction measurement, it is shown that the composition of the ternary ZnSTe QDs is independent of the growth duration. From the PL measurement, a strong quantum confinement effect was observed in the spectra. The emission can persist up to room temperature, which is an indication of the strong exciton effect in the quantum dot structure. In the temperature dependence of the PL measurement, the activation energy was found to increase with decreasing dot size. This exciton binding energy in the ZnSTe/ZnS QDs structure, we obtain that the value of the exciton binding energy is in the result implies that the activation energy giving rise to the thermal quench effect is dominated by the exciton binding energy. According to the theoretical calculation of the order of 100meV, which is consistent with our experimental results. We therefore conclude that ternary ZnSTe quantum dots can be successfully grown by our simple method.
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LIAO, DE-AN, e 廖得安. "One-pot Synthesis of Ag-In-S Ternary Quantum Dots". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/74m9h7.

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Abstract (sommario):
碩士
國立高雄師範大學
化學系
106
This thesis reports the one-pot synthesis of ternary ZAIS/ZnS core-shell quantum dots. Three metal precursor complexes were obtained firstly by the reactions of, silver, indium and zinc nitrates and dithiocarbamate. The ZAiS/Zns were obtained by the one-pot synthesis method by usingoleyamine as solvent and protective agent. The product identification and purity analysis were carried out by nuclear magnetic resonance spectroscopy and elemental analysis. The optical properties of ZAIS/ZnS core-shell quantum dots were analyzed by visible UV spectrophotometer and the fluorescence spectrometer. Finally, quantum dots were determined by transmission electron microscopy and elemental analysis to confirm the size and crystal structure. The results of this thesis show that ZAIS/ZnS quantum dots with good thermal stability and high quantum yield could be obtained by one-pot synthesis method successfully.
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Tseng, Chih-Hsiang, e 曾致翔. "Preparation and optical properties study of CdSeS ternary composition quantum dots". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/21241507125191553885.

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Abstract (sommario):
碩士
國立臺灣科技大學
化學工程系
97
In this study, CdSeS quantum dots (QDs) were synthesized via non-coordinated system. The structural model of CdSeS QDs was established by using composition analysis, absorption spectroscopy and emission spectroscopy. When the molar ratio of II group element and VI group element was employed to control the structure of CdSeS QDs, we found that CdSeS QDs would precipitate easily if VI group element was excess and CdSeS QDs with high photoluminescence quantum yield (PL QY) could be produced if II group element was excess. In addition, the emission wavelength and PL QY could be modulated by controlling the composition ratio of Se and S in the injection stock solution. The emission wavelength of CdSeS QDs shifts to short wavelength and PL QY could also increase with increasing the composition of S. The results demonstrated that the band gap of CdSeS QDs was not only tunable with size, but also with composition of reactant. In the study, we also used composition analysis, size distribution and absorption spectroscopy to speculate the structural model of CdSeS QDs by gradient or core-shell model successfully. Additionally, the influence of different surfactants on the recombination of electron-hole pairs inside the CdSeS QDs was also be discussed. When suitable surfactant was chose to passivate the surfaces of CdSeS QDs, PL QY could increase to 91%.

Libri sul tema "Ternary quantum dots":

1

Ternary Quantum Dots. Elsevier, 2021. http://dx.doi.org/10.1016/c2018-0-03690-7.

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Oluwafemi, Oluwatobi Samuel, El Hadji Mamour Sakho, Sundararajan Parani e Thabang Calvin Lebepe. Ternary Quantum Dots: Synthesis, Characterization, and Applications. Elsevier Science & Technology, 2020.

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Oluwafemi, Oluwatobi Samuel, El Hadji Mamour Sakho, Sundararajan Parani e Thabang Calvin Lebepe. Ternary Quantum Dots: Synthesis, Characterization, and Applications. Elsevier Science & Technology, 2020.

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Capitoli di libri sul tema "Ternary quantum dots":

1

Pain, Puspak, Arindam Sadhu, Kunal Das e Maitreyi Ray Kanjilal. "Physical Proof and Simulation of Ternary Logic Gate in Ternary Quantum Dot Cellular Automata". In Computational Advancement in Communication Circuits and Systems, 375–85. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8687-9_34.

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Bhoi, Bandan Kumar, Neeraj Kumar Misra, Ipsita Dash e Ankita Patra. "A Redundant Adder Architecture in Ternary Quantum-Dot Cellular Automata". In Smart Intelligent Computing and Applications, 375–84. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9282-5_35.

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Pecar, Primoz, e Iztok Lebar Bajec. "The Key Elements of Logic Design in Ternary Quantum-Dot Cellular Automata". In Lecture Notes in Computer Science, 177–88. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21341-0_21.

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Karmakar, Supriya. "Quantum Dot Gate Field-Effect Transistor (QDGFET): Circuit Model and Ternary Logic Inverter". In Novel Three-state Quantum Dot Gate Field Effect Transistor, 65–80. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1635-3_6.

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Karmakar, Supriya. "Performance in Sub-25-nm Range: Circuit Model, Ternary Logic Gates and ADC/DAC". In Novel Three-state Quantum Dot Gate Field Effect Transistor, 105–26. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1635-3_8.

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Tapna, Suparba, Kisalaya Chakrabarti e Debarka Mukhopadhyay. "Performance Analysis of Logical Structures Using Ternary Quantum Dot Cellular Automata (TQCA)-Based Nanotechnology". In Third Congress on Intelligent Systems, 421–41. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9379-4_31.

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Tapna, Suparba, Kisalaya Chakrabarti e Debarka Mukhopadhyay. "A Novel Architecture of Flip-Flop for Processor-In-Near-Memory (PINM) using Ternary Quantum-Dot Cellular Automata (TQCA)". In Computational Intelligence in Pattern Recognition, 413–25. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2543-5_35.

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Oluwafemi, Oluwatobi Samuel, El Hadji Mamour Sakho, Sundararajan Parani e Thabang Calvin Lebepe. "Ternary semiconductor nanocomposites". In Ternary Quantum Dots, 77–115. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-818303-8.00002-2.

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Oluwafemi, Oluwatobi Samuel, El Hadji Mamour Sakho, Sundararajan Parani e Thabang Calvin Lebepe. "Cytotoxicity of ternary quantum dots". In Ternary Quantum Dots, 137–53. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-818303-8.00011-3.

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Oluwafemi, Oluwatobi Samuel, El Hadji Mamour Sakho, Sundararajan Parani e Thabang Calvin Lebepe. "Properties of ternary quantum dots". In Ternary Quantum Dots, 35–45. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-818303-8.00004-6.

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Atti di convegni sul tema "Ternary quantum dots":

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Yang, Heesun, Sun-Hyoung Lee, Dae-Yeon Jo, Suk-Young Yoon, Hyun-Min Kim, Jee-Na Han e Young-Ju Lee. "Ternary ZnSeTe Quantum Dots as efficient visible emitters". In International Online Conference on Hybrid Materials and Optoelectronic Devices. València: Fundació Scito, 2021. http://dx.doi.org/10.29363/nanoge.hybridoe.2021.008.

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Abu Bakar, Norhayati, Akrajas Ali Umar, Muhamad Mat Salleh, Muahamad Yahaya e Burhanuddin Yeop Majlis. "Highly red luminescence properties from ternary ZnCdTe quantum dots". In Second International Conference on Smart Materials and Nanotechnology in Engineering, a cura di Jinsong Leng, Anand K. Asundi e Wolfgang Ecke. SPIE, 2009. http://dx.doi.org/10.1117/12.839808.

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Elim, Hendry I., Wei Ji, Lu Tian, Meng-Tack Ng e Jagadese J. Vittal. "Large nonlinear optical properties of ternary quantum dots and nanorods". In NanoScience + Engineering, a cura di Zeno Gaburro e Stefano Cabrini. SPIE, 2007. http://dx.doi.org/10.1117/12.730934.

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Deviprasad, Vidya, Hemant Ghadi, Debabrata Das, Debiprasad Panda e Subhananda Chakrabarti. "Impact of ternary capping on p-i-p InAs/GaAs quantum-dot infrared photodetectors". In Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XVI, a cura di Diana L. Huffaker e Holger Eisele. SPIE, 2019. http://dx.doi.org/10.1117/12.2508669.

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Rahmi, Aidhia, Akrajas Ali Umar, Muhammad Mat Salleh, Burhanuddin Yeop Majlis e Muhammad Yahya. "Enhanced-photoluminescence properties of CdTe quantum dots prepared from the ternary surfactant mixture system". In 2010 IEEE International Conference on Semiconductor Electronics (ICSE). IEEE, 2010. http://dx.doi.org/10.1109/smelec.2010.5549568.

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Ünlü, Hilmi. "Modelling of CdSe/CdZnS and ZnSe/CdZnS binary/ternary heterostructure core/shell quantum dots". In TURKISH PHYSICAL SOCIETY 33RD INTERNATIONAL PHYSICS CONGRESS (TPS33). Author(s), 2018. http://dx.doi.org/10.1063/1.5025975.

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Daveau, Nicolas, Marie Moreau, Annette Delices, Yanxia Hou, Céline Rivaux, Wai-Li Ling, Peter Reiss, Kuntheak Kheng e Didier Gasparutto. "Ternary AgInS2 Quantum Dots: Synthesis and DNA Grafting for Biosensing Applications". In 2023 IEEE 23rd International Conference on Nanotechnology (NANO). IEEE, 2023. http://dx.doi.org/10.1109/nano58406.2023.10231192.

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Oskolkova, Tatiana, Ekaterina Smirnova, Lyubov Borodina, Elena Svirshchevskaya, Andrey Veniaminov e Anna Orlova. "FRET-Enhanced Singlet Oxygen Generation by Nanocomposites Based on Ternary AgInS2/ZnS Quantum Dots and Porphyrin Derivatives". In 7th International Conference on Theoretical and Applied Nanoscience and Nanotechnology. Avestia Publishing, 2023. http://dx.doi.org/10.11159/tann23.148.

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Ghadi, H., S. Adhikary, S. Shetty, A. Balgarkashi e S. Chakrabarti. "A detail investigation on quaternary and ternary capped strain coupled quantum dots based infrared photodetectors and effect of rapid thermal annealing temperature". In SPIE Sensing Technology + Applications, a cura di Nibir K. Dhar e Achyut K. Dutta. SPIE, 2015. http://dx.doi.org/10.1117/12.2180908.

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Pecar, Primoz, Miha Janez, Nikolaj Zimic, Miha Mraz e Iztok Lebar Bajec. "The Ternary Quantum-dot Cellular Automata Memorizing Cell". In 2009 IEEE Computer Society Annual Symposium on VLSI. IEEE, 2009. http://dx.doi.org/10.1109/isvlsi.2009.32.

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Rapporti di organizzazioni sul tema "Ternary quantum dots":

1

Wang, Wenyong, Jinke Tang, Yuri Dahnovsky, Jon M. Pikal e TeYu Chien. Quantum Dot Sensitized Solar Cells Based on Ternary Metal Oxide Nanowires. Office of Scientific and Technical Information (OSTI), novembre 2017. http://dx.doi.org/10.2172/1406887.

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