Academic literature on the topic 'CdSe nanoparticle'
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Journal articles on the topic "CdSe nanoparticle"
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Ishak, Mohamad Nizam, K. A. Yaacob, and Ahmad Fauzi Mohd Noor. "The Effect of Ligands on CdSe Nanoparticle Films Deposited by EPD." Advanced Materials Research 1087 (February 2015): 304–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1087.304.
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Nanoparticle from group II-IV semiconductor nanoparticles is widely studied for solar cells. The ability to modify the surface of nanoparticle is significant to successful use in various applications. In this research, mercaptoundecionic acid (MUA) and trioctyl phosphine oxide (TOPO) were used as ligand for cadmium selenide (CdSe) nanoparticles. The wavelength shift to a shorter value observed due to decreasing size of CdSe nanoparticle after ligand exchange from TOPO to MUA. The electrophoretic deposition methods (EPD) have being employed to deposite CdSe nanoparticles films on fluorine doped tin oxide (FTO). The deposition voltages used are between 100 - 400 V for 15 minutes. From SEM results show the formation layer of CdSe nanoparticles capped with MUA is strong and porous as compared to CdSe nanoparticle capped with TOPO. MUA capped CdSe shows better cell efficiency compared to TOPO capped CdSe which is 0.1735 %.
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Hu, Siyi, Yu Ren, Yue Wang, Jinhua Li, Junle Qu, Liwei Liu, Hanbin Ma, and Yuguo Tang. "Surface plasmon resonance enhancement of photoluminescence intensity and bioimaging application of gold nanorod@CdSe/ZnS quantum dots." Beilstein Journal of Nanotechnology 10 (January 3, 2019): 22–31. http://dx.doi.org/10.3762/bjnano.10.3.
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Biological applications of core/shell near-infrared quantum dots (QDs) have attracted broad interest due to their unique optical and chemical properties. Additionally, the use of multifunctional nanomaterials with near-infrared QDs and plasmonic functional nanoparticles are promising for applications in electronics, bioimaging, energy, and environmental-related studies. In this work, we experimentally demonstrate how to construct a multifunctional nanoparticle comprised of CdSe/ZnS QDs and gold nanorods (GNRs) where the GNRs were applied to enhance the photoluminescence (PL) of the CdSe/ZnS QDs. In particular, we have obtained the scattering PL spectrum of a single CdSe/ZnS QD and GNR@CdSe/ZnS nanoparticle and comparison results show that the CdSe/ZnS QDs have an apparent PL enhancement of four-times after binding with GNRs. In addition, in vitro experimental results show that the biostability of the GNR@CdSe/ZnS nanoparticles can be improved by using folic acid. A bioimaging study has also been performed where GNR@CdSe/ZnS nanoparticles were used as an optical process for MCF-7 breast cancer cells.
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I. Korsunskiy, Vladimir, Reinhard B. Neder, Andreas Hofmann, Sofia Dembski, Christina Graf, and Eckart Rühl. "Aspects of the modelling of the radial distribution function for small nanoparticles." Journal of Applied Crystallography 40, no. 6 (November 10, 2007): 975–85. http://dx.doi.org/10.1107/s0021889807038174.
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An approach to modelling radial distribution functions (RDFs) of nanoparticle samples over a wide range of interatomic distances is presented. Two different types of contribution to the model RDF are calculated. The first explicitly reflects the structure of the nanoparticle parts with more or less crystalline atomic structure. It can be calculated precisely and contains comparatively sharp peaks, which are produced by the set of discrete interatomic distances. The second includes RDF contributions from distances between weakly correlated atoms positioned within different nanoparticles or within different parts of a nanoparticle model. The calculation is performed using the approximation of a uniform distribution of atoms and utilizes the ideas of the characteristic functions of the particle shape known in small-angle scattering theory. This second RDF contribution is represented by slowly varying functions of interatomic distancer. The relative magnitude of this essential part of the model RDF increases with increasingrcompared with the part that represents the ordered structure. The method is applied to test several spherical and core/shell models of semiconductor nanoparticles stabilized with organic ligands. The experimental RDFs of ZnSe and CdSe/ZnS nanoparticle samples were obtained by high-energy X-ray diffraction at beamline BW5, HASYLAB, DESY. The ZnSe nanoparticles have a spherical core with approximately 26 Å diameter and zincblende structure. The RDF of the CdSe/ZnS nanoparticle sample shows resolved peaks of the first- and the second-neighbour distances characteristic for CdSe (2.62 and 4.27 Å) and for ZnS (2.33 and 3.86 Å) and for the first time clearly confirms the presence of CdSe and ZnS nanophases in such objects. The diameters of the CdSe and ZnS spherical cores are estimated as 27 and 15 Å. CdSe and ZnS are present in the sample for the most part as independent nanoparticles. A smaller amount of ZnS forms an irregularly shaped shell around the CdSe cores, which consists of small independently oriented ZnS particles.
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Pundyk, Iryna, Igor Dmitruk, M. Davydenko, V. Romanyuk, and A. Kasuya. "Relaxation of Resonant Excitons in CdSe Nanocrystals: Simple Variational Calculation." Advanced Materials Research 222 (April 2011): 170–74. http://dx.doi.org/10.4028/www.scientific.net/amr.222.170.
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The details of energy relaxation and multiple phonon scattering of a resonantly excited electron-hole pair confined in CdSe nanoparticle are studied at low temperature. Simple variational calculation of Ritz type have been performed to explain relaxation of excitons resonantly excited in CdSe nanoparticles in the case if initial photon absorption and creation of electron-hole pair takes place in the peripheral part of nanoparticle.
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Расмагин, С. И., and И. К. Новиков. "Оптические свойства наночастиц CdSe/ZnS в пленках термообработанного поливинилхлорида." Журнал технической физики 53, no. 4 (2019): 508. http://dx.doi.org/10.21883/ftp.2019.04.47450.9016.
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AbstractComposites based on polyvinylchloride with incorporated CdSe/ZnS nanoparticles are produced. The optical and electrical properties of the polymer composites containing CdSe/ZnS nanoparticles are studied. The absorption and photoluminescence spectra of the composites are recorded, and their bulk resistivities are measured. The CdSe nanoparticle dimensions are determined. It is established that, upon short-term heat treatment, the photoluminescence intensity increases, whereas upon heating for a long time, the photoluminescence intensity substantially decreases.
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Saran, Amit D., and Jayesh R. Bellare. "CdSe Quantum Dots to Quantum Rods: Transition Studies and Evaluation of Sensitivity as Transducers for Biosensing Glucose." Nanoscience & Nanotechnology-Asia 10, no. 1 (January 23, 2020): 29–38. http://dx.doi.org/10.2174/2210681208666180927105629.
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Background: The estimation of glucose level in the blood serum, has been widely used as a clinical indicator of diabetes. Optical and electrochemical sensing of glucose widely uses Glucose Oxidase (GOD) enzyme, as the catalyst for glucose oxidation, which releases hydrogen peroxide (H2O2). Optical biosensors are superior to their electrochemical counter-parts as they are resistant to electromagnetic interference, easier to fabricate into a microdevice and require low power supply. The quantum-dot-based biosensors work on the phenomenon of fluorescence quenching following the release of H2O2. Methods: The CdSe nanoparticles are prepared in two series by room-temperature microemulsion method. In series A, only AOT surfactant is used to synthesize spherical CdSe nanoparticles. In series B, the mixed surfactant system of AOT and lecithin is used to synthesize anisotropic CdSe. The morphology and crystallography is studied as the CdSe shape changes from spherical to rod-like. As the CdSe nanoparticles are studied from spherical to rod-like morphology, the transducing sensitivity of these nanoparticles is evaluated with respect to glucose biosensing. The effects of size and shape are studied, based on the fluorescence quenching by H2O2 solutions. The sensitivity of proposed nanoparticles, is evaluated as a function of size, shape, surface area and number concentration of CdSe nanoparticles. Results: The spherical CdSe nanoparticles are found to increase in size as R(water-to-surfactant ratio) is increased from 4 to 12, in series A. Also, the aspect ratio of CdSe nanoparticle is found to increase from 4.2 to 12.8 as the ratio of AOT to lecithin is varied from 1:0.5 to 1:3. The decrease in sensitivity index is seen with increasing surface area for both series A and B. The sensitivity is decreasing again with increasing maximum dimension of the CdSe nanoparticle in the dispersion. While the trend is reverse in case of the number concentration for CdSe nanoparticles synthesized in series B. Conclusion: From the data presented, it can be safely concluded that the sensitivity indices for series A are better than those for series B, for the same values of a) the total surface area of CdSe nanoparticles, b) total number concentration, and c) maximum dimension of CdSe nanoparticles. Also, the single surfactant system (series A) is simple, cheaper and more reproducible to synthesize the CdSe nanosheres, as compared with the mixed surfactant system forming CdSe quantum rods (series B). With these points, it is reasonable to report that CdSe spherical QDs are better candidates for glucose biosensing, as compared to CdSe quantum rods.
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Vasan, R., F. Gao, M. O. Manasreh, and C. D. Heyes. "Investigation of charge transport between nickel oxide nanoparticles and CdSe/ZnS alloyed nanocrystals." MRS Advances 2, no. 51 (2017): 2935–41. http://dx.doi.org/10.1557/adv.2017.488.
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ABSTRACTCharge transport between nickel oxide nanoparticles and CdSe/ZnS alloyed core/shell nanocrystals is investigated. The crystal structure and composition of the nickel oxide nanoparticles are evaluated using X-ray diffraction, Raman and X-ray photoelectron spectroscopies. The nanoparticles are near-stoichiometric with very low defect densities. The optical properties of the materials are studied by measuring the absorbance and time resolved photoluminescence spectra. The band gap of the nickel oxide nanoparticles is around 4.42 eV. The CdSe/ZnS nanocrystals exhibit shorter average lifetimes when mixed with nickel oxide nanoparticle powder. The lifetime quenching can be attributed to the efficient charge transport from the CdSe/ZnS nanocrystals to nickel oxide nanoparticles due to the relative valence band alignment.
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Emin, Saim, Ceco Dushkin, Seiichiro Nakabayashi, and Eiki Adachi. "Growth kinetics of CdSe nanoparticles synthesized in reverse micelles using bis(trimethylsilyl) selenium precursor." Open Chemistry 5, no. 2 (June 1, 2007): 590–604. http://dx.doi.org/10.2478/s11532-007-0018-8.
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AbstractWe first focus on the kinetics of nanoparticle growth in a microemulsion synthesis of CdSe semiconductor nanocrystals. The process consists of a fast initial stage of typical time constant of the order of 103 s followed by a slow stage of time constant of the order of 104s. Growth proceeds similarly to that described for the hot-matrix synthesis of CdSe, underlining the generality of the two-stage growth mechanism, irrespective of the matrix type and synthesis conditions. However, the time constant of each stage in the microemulsion synthesis is much larger than in the hot-matrix one. Also, the ratio between the fast and slow time constant is appreciably bigger. We also prove that larger size reverse micelles, obtained by increasing the water:surfactant ratio, generally lead to larger CdSe nanoparticles. Bis(trimethylsilyl) selenium is the crucial precursor for the CdSe nanoparticle synthesis. An intermediate stage of the chemical reaction limiting the bis(trimethylsilyl) selenium production is described theoretically.
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Conner, Ava E., Veronica Gordillo-Herrejon, Sonia C. Francone, Emily A. Shriner, Fernando E. Acosta, Nathan D. Barnett, and Deon T. Miles. "Limiting the Growth of Water-Soluble, Monolayer-Protected Quantum Dots." International Journal of Analytical Chemistry 2018 (July 2, 2018): 1–6. http://dx.doi.org/10.1155/2018/3164347.
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The growth and solubility of quantum dots (QDs) are important factors that must be examined before these nanoparticles are incorporated into a variety of potential applications. In this work, monolayer-protected CdSe QDs surrounded by water-soluble thiols were prepared using various cadmium salts. The use of a variety of cadmium salts did not have a significant impact on the spectral properties of the CdSe QDs. CdSe QDs were synthesized at rather low temperatures (< 0°C), resulting in slow nanoparticle growth upon subsequent heating of the reaction mixture. The effect of multiple drying and redissolving cycles of the QD samples was examined. The effect of heating temperature on QD growth was studied, with more rapid nanoparticle growth associated with higher temperatures. The results show that QDs can be synthesized at low temperatures and their subsequent growth can be controlled during the heating process.
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Zeng, Qinghui, Xianggui Kong, Youlin Zhang, and Hong Zhang. "Highly Luminescent CdSe/ZnSe Core–Shell Quantum Dots of One-Pot Preparation in Octadecene." Journal of Nanoscience and Nanotechnology 8, no. 3 (March 1, 2008): 1346–49. http://dx.doi.org/10.1166/jnn.2008.18194.
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CdSe/ZnSe core–shell quantum dots were synthesized using a new one-pot procedure where the core was prepared in octadecene. A ZnSe shell around a CdSe nanoparticle was formed by the reaction of selenium-richness on the surfaces of CdSe nanoparticles with Zn2+ from the injected zinc stearate precursor. The optical properties, luminescence kinetics, and the effect of shell thickness of as-prepared QDs were studied, which verifies the high quality of the resulting QDs. The new approach is effective not only for preparing core/shell QDs, but also for reducing the complexity of synthesis, toxicity, and reagent cost.
Dissertations / Theses on the topic "CdSe nanoparticle"
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Hill, Lawrence J. "Synthesis and Dipolar Assembly of Cobalt-Tipped CdSe@CdS Nanorods." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/332684.
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This dissertation contains four chapters with advances relevant to the fields of nanoparticle synthesis and nanoparticle self-assembly: a review of nanoparticle self-assembly, or “colloidal polymers”; dumbbell heterostructured nanorod synthesis; dipolar matchstick heterostructured nanorod synthesis; and self-assembly of dipolar matchsticks to form colloidal polymers. These chapters are followed by appendices containing supporting data for chapters two through four. The first chapter is a review summarizing current research involving the 1-D assembly of nanocrystals to form “colloidal polymers.” One of the major goals of materials chemistry is to synthesize hierarchical materials with precise controlled particle ordering covering all length scales of interest (termed, the “bottom up” approach). Recent advances in the synthesis of inorganic colloids have enabled the construction of complex morphologies for particles in the range of 1 – 100 nm. The next level of structural order is to control the structure of assemblies formed from these materials. Linear nanoparticle assemblies are particularly challenging to achieve due to the need to impart functionality to colloids such that (typically) only two sites are active per particle. An emerging idea in the literature which addresses this challenge is to consider linear assemblies of inorganic nanoparticles as colloidal analogs to traditional polymers. This conceptual framework has enabled the formation of linear assemblies having controlled composition (to form segmented and statistical copolymers), architecture (linear, branched, cyclic), and degree of polymerization (chain length). However, this emerging field of synthesizing colloidal polymers has not yet been reviewed in terms of methods to control fundamental polymer parameters. Therefore, linear nanoparticle assembly is reviewed in chapter 1 by applying concepts from traditional polymer science to nanoparticle assembly. The emphasis of chapter 1 is on controlling degree of polymerization, architecture, and composition for colloidal polymers, and seminal examples are highlighted which control these parameters. The second chapter is centered on a novel methodology to install ferromagnetic cobalt domains onto core@shell, “CdSe@CdS” nanorods. While the structures synthesized in this work were novel, the key advance from this work was the development of a methodology to separate nanorod activation from deposition of ferromagnetic cobalt domains onto semiconductor nanorods. As synthesized CdSe@CdS nanorods are passivated with strongly binding phosphonic acid ligands, and these ligands prevent direct deposition of many materials (such as cobalt). Synthetic methods must therefore modify nanorod surfaces prior to deposition of additional nanoparticle domains (tips). Previous synthetic methods for the deposition of magnetic domains onto nanorod termini typically combined activation of nanorod termini and metal deposition into a single synthetic step. While these previous reports were successful in achieving tipped nanorods, the coupling of these two reactions required matching the kinetics of nanorod activation and decomposition/reduction of metal precursors in order to achieve the desired heterostructure morphology. However, the presence of ligands used for nanorod activation can also affect the rate of metal precursor decomposition/reduction and the propensity of the metal to form free nanoparticles through homogeneous nucleation. Thus, simultaneous nanorod activation and metal deposition hinders modification of these syntheses to obtain differing heterostructured morphologies. In the work presented in chapter 2, we chemically activate nanorod termini towards cobalt deposition in a separate chemical step from deposition of metallic cobalt nanoparticle domains. First, reductive platinum deposition conditions were utilized to activate nanorod termini towards the deposition of cobalt domains, which were deposited in a subsequent reaction step. Then, the kinetics of nanorod activation during platinum deposition were tracked, and the platinum-tipped nanorod morphologies were correlated with the results of subsequent cobalt deposition reactions. Ultimately, controlled placement of cobalt domains onto one or both nanorod termini was demonstrated based on the degree of activation during platinum deposition. Cobalt nanoparticle tips were then selectively oxidized to form CoₓOy-tipped nanorods, which were a novel class of p-n type nanomaterials achieved over a total of five synthetic steps. Relevant supporting details for the synthesis of these dumbbell tipped nanorods are provided in Appendix A. The third chapter describes the synthesis of CoNP-tipped nanorods with a single, strongly dipolar, ferromagnetic CoNP-tip per nanorod. The key synthetic advance was the ability to activate a single terminus per nanorod without activation of lateral nanorod facets, which was vital in achieving these larger, dipolar, cobalt tips (rather than lateral decoration of cobalt onto nanorod lateral facets). These dipolar “matchstick” CoNP-tipped nanorods then spontaneously formed linear assemblies carrying nanorod side chains as pendant functionality. Activation of CdSe@CdS nanorods was found to occur through the deposition of small (< 2 nm) PtNP-tips which were not readily observable by standard characterization techniques. The finding that small (< 2 nm) PtNP-tips altered nanorod reactivity towards cobalt deposition emphasized the effect of subtle changes to nanorod surface chemistry. Relevant supporting details for the synthesis of these dipolar matchstick tipped nanorods are provided in appendix B. The fourth chapter is centered on the self-assembly of dipolar matchstick cobalt-tipped nanorods to form colloidal (co)polymers reminiscent of traditional bottlebrush polymers, with controlled composition and phase behavior on carbon surfaces. Similar to earlier findings in traditional polymer science, nanorod side chain length was found to significantly impact surface assembly of these colloidal analogs of bottlebrush copolymers, which provided a useful parameter for affecting surface wetting and phase behavior of nanoparticle thin films. This work was also the first demonstration of colloidal copolymers from the dipolar assembly of magnetic nanoparticles, where both segmented and statistical copolymer compositions were achieved. We then demonstrated, for the first time, that a colloidal copolymer with segmented composition can form a mesoscopic phase separated morphology which is similar to that observed for traditional block copolymers. This key advance opens the possibility of controlling structural ordering over still longer length scales by the development of methods to control phase separated morphologies in a manner similar to traditional block copolymers. Relevant supporting details for the synthesis and assembly of these colloidal bottlebrush polymers are provided in appendix C.
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Doherty, Rachel Pamela. "Preparation and characterisation of CdSe quantum dots : a nanoparticle photoelectrode." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432974.
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Antonello, Alessandro. "MULTIFUNCTIONAL NANOSTRUCTURED MATERIALS BASED ON CdSe AND TiO2 NANOPARTICLES." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3421896.
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Nanotechnology has arisen as one of the most important fields in recent research, for the implications in both basic and applied science and technological applications.
The manipulation of matter at the nanoscale is accompanied by the appearance of novel properties and large surface to volume ratio which can be exploited in a number of applications ranging from optics, catalysis and sensing, to name a few.
In this work, we mainly focused on the synthesis and the use of nanomaterials for the preparation of nanocomposites and structures to be employed in the optical field. The main advantage of introducing nanosized inclusions in a host material is that specific functionalities or desired optical change can be imparted while transparency in the visible range can be retained.
The whole activity can be divided in the synthesis and processing of nanoparticles and in their usage for some specific application.
Cadmium selenide (CdSe), Titanium dioxide and layered titanates have been mainly addressed due to PL emission properties and high refractive index. In addition, zinc sulfide (ZnS) nanoparticles have been synthesized.
CdSe nanoparticles (Quantum Dots) have been obtained by colloidal chemistry and part of the work has been spent in the synthesis of core-shell nanoparticles with a CdSe core and a shell of semiconductor materials with wider band gap in order to increase the stability of the emission properties of such materials. These nanoparticles were introduced in sol-gel derived ZrO2 waveguides to obtain materials showing optical gain which was characterized by ASE (Amplified Spontaneous Emission) experiments.
High refractive index materials are useful in many optical applications. High refractive index depositions were obtained introducing Titania nanoparticles in proper matrices.
A sol-gel synthesis for titanium dioxide nanoparticles has been developed yielding to anatase particles in the 3-5 nm range. These were embedded in an epoxy-based hybrid material obtaining transparent depositions with refractive index in the 1.51-1.89 range.
Layered titanates were further addressed since they allowed extending the processing and engineering of titanium oxide materials. A synthetic colloidal procedure was developed, in which titanate nano-sheets are produced by reaction of a titanium alkoxide and an organic base.
These materials allowed to obtained composites with multifumctional properties since materials embedding both titanate sheets and quantum dots could be obtained and applied in PL active waveguide and functional coating for LED devices to improve light extraction and produce white light through down-conversion. Coatings for LED were also developed using conventional sol-gel derived hybrid materials.
The obtained layered titanates could also be modified and treated by UV curing, leading to material’s densification and enhancement of the refractive index at relatively low temperatures (200 °C). This processing behavior has been exploited in Bragg mirror fabrication and vertical optical microcavity incorporating quantum dots. The procedure employed for microcavity fabrication was found to be effective in keeping the optical properties of quantum dots, allowing for optical characterization of this structure.
The properties of titanium dioxide have been exploited for optical gas sensing applications embedding gold nanoparticles in a crystalline TiO2 matrix. Anatase TiO2 particles have been successfully used as matrix material for this application. The employed preparation of such nanocomposites allowed tailoring of porosity and gold-titania interface which could be studied by optical measurements. Optical sensing was evidenced by variation in thin film absorbance at wavelengths near the plasmon resonance of gold nanoparticles caused by the presence of the gas analytes.
Gold nanorods were introduced in the synthesized titanates. Gold nanorods are known to spheroidise upon thermal treatment, losing their peculiar optical properties. We found that the processing treatments developed for titanates resulted in improved thermal stability of such nanostructures as shown by optical measurements. This result is very interesting since it would allow extending gold nanorods’s exploitation in optical applications.
Finally, composites with enhanced refractive index were realized by introducing ZnS nanoparticles in hybrid sol-gel material. A synthesis of ZnS nanoparticles has been developed, which allows nanoparticles functionalization and introduction in a hybrid organic-inorganic sol-gel matrix.Il campo delle nanotecnologie è diventato tra i più importanti nella recente ricerca scientifica. È’ un settore multidisciplinare nelle conoscenze che ne costituiscono le basi e trova applicazione in svariati ambiti della tecnologia. La manipolazione della materia su nanometrica è accompagnata dalla comparsa di nuove proprietà ed un elevato valore di superficie per unità di volume. Queste proprietà possono essere sfruttate in applicazioni nei campi dell’ottica, della catalisi e della sensoristica, per non citarne che alcuni. In questo lavoro, l’attività è stata principalmente focalizzata sulla sintesi e l’uso di materiali nanostrutturati per la preparazione di nanocompositi e strutture di interesse nel campo dell’ottica. Il vantaggio principale nell’ introdurre particelle nanometriche in un materiale risiede nella possibilità di introdurre specifiche funzionalità o variazioni nelle proprietà ottiche mantenendo nello stesso tempo la trasparenza nel visibile. L’intera attività può essere divisa nella sintesi e successiva manipolazione di nanoparticelle e nel loro uso in specifiche applicazioni. Seleniuro di Cadmio (CdSe), Biossido di Titanio (TiO2) e Titanati a strati sono stati principalmente presi in considerazione per sfruttare specifiche proprietà di fotoluminescenza e di elevato indice di rifrazione. Sono inoltre state sintetizzate nanoparticelle di Solfuro di Zinco (ZnS). Nanoparticelle di CdSe, anche chiamate Quantum Dots (QDs), sono state ottenute attraverso sintesi di tipo colloidale. Parte del lavoro è stata dedicata al ricoprimento di queste nanoparticelle con semiconduttori a più elevato band gap con lo scopo di aumentare la stabilità delle proprietà di emissione di questi materiali. Queste nanoparticelle sono state introdotte in guide d’onda costituite da Biossido di Zirconio (ZrO2) ottenuto per via sol-gel per ottenere materiali con proprietà di guadagno ottico testate in esperimenti di emissione spontanea amplificata (ASE). Materiali ad alto indice di rifrazione trovano utilizzo in molte applicazioni ottiche. Deposizioni a elevato indice di rifrazione sono state ottenute introducendo particelle di biossido di titanio in opportune matrici. E’ stata sviluppata una sintesi di tipo sol-gel in grado di produrre soluzioni colloidali stabili di particelle cristalline con la struttura cristallografica dell’anatase con diametro intorno a 3-5 nm. Queste nanoparticelle sono state introdotte in una matrice ibrida sol-gel ottenendo deposizioni trasparenti con indice di rifrazione variabile tra 1.51 e 1.89. Sono stati successivamente presi in considerazione i titanati a strati perché permettono di estendere le possibilità di manipolazione ed ingegnerizzazione di materiali a base di ossido di titanio. È stata sviluppata una sintesi colloidale in cui “foglietti“ nanometrici di titanati sono prodotti per reazione di un alcossido di titanio e una base organica. Questi materiali hanno permesso di ottenere compositi con proprietà multifunzionali. Infatti, materiali contenenti titanati lamellari e QDs sono stati ottenuti e applicati in guide d’onda con proprietà di fotoluminescenza e ricoprimenti funzionali su dispositivi LED per migliorare la frazione di luce estratta e produrre luce bianca per conversione di parte della luce emessa in luce a lunghezza d’onda maggiore. Ricoprimenti per LED sono inoltre stati sviluppati con materiali ibridi sol-gel più convenzionali. I titanati stratificati sono stati trattati utilizzando radiazione UV. Questo genere di trattamento porta a una densificazione del materiale con conseguente aumento dell’indice di rifrazione impiegando durante il processo temperature relativamente basse (200 °C). Questo trattamento è stato impiegato nella fabbricazione di specchi multistrato dielettrici e cavità ottiche verticali dove sono stati inseriti QDs come emettitori luminescenti. Il metodo utilizzato è stato verificato essere compatibile con la conservazione delle proprietà di emissione dei Quantum Dots, permettendo la caratterizzazione ottica delle strutture sviluppate. Sono state inoltre considerate applicazioni sensoristiche per il rilevamento di gas tramite misure ottiche di materiali a base di TiO2 contenenti nanoparticelle d’oro. Le nanoparticelle di anatase in precedenza menzionate sono state adoperate come matrice, consentendo sia di agire sulla porosità, sia di caratterizzare l’interfaccia oro/titania tramite misure ottiche. La funzionalità sensoristica è stata determinata studiando la variazione nell’assorbanza ottica a lunghezze d’onda vicine alla risonanza plasmonica delle particelle d’oro, causata dalla presenza di uno specifico gas nell’atmosfera. Nanorods di oro sono stati inseriti in matrici di titanati lamellari. Queste nanostrutture d’oro tendono ad assumere la forma sferica in seguito a trattamento termico perdendo così le loro specifiche proprietà. Il trattamento di densificazione sviluppato per i titanati è stato applicato per questi compositi, fornendo una migliore stabilità termica dei nanorods, come dimostrato da misure ottiche. Questo risultato è interessante poiché potrebbe permettere di estendere l’utilizzo di queste nanostrutture in applicazioni ottiche. Infine, sono stati realizzati compositi con aumentato indice di rifrazione utilizzando particelle di solfuro di zinco per le quali è stata sviluppata una sintesi colloidale e una procedura di funzionalizzazione per il loro inserimento in matrici ibride sol-gel.
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Yaacob, Khatijah Aisha. "Formation and characterisation of CdSe-TiO2 nanoparticle films by electrophoretic deposition." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6917.
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Electrophoretic deposition (EPD) was used to form a composite layer of mercaptoundeconic acid (MUA) capped CdSe-TiO2 nanoparticle on a fluorine doped indium tin oxide (FTO) substrate. The CdSe-TiO2 layer can be employed to fabricate a quantum dot sensitized solar cells (QDSSC), increased contact between CdSe and TiO2 nanoparticles and leading to improved efficiency of the solar cells. A colloidal suspension of TOPO capped CdSe nanoparticles was prepared by the hot injection method, followed with ligand exchange in order to produce MUA capped CdSe nanoparticles. CdSe particle of diameter in the range of 2.44 nm to 3.26 nm were to be used in this research. The TiO2 nanoparticles were prepared by hydrolysis of titanium isopropoxide in water and produced particles size of 4.66 nm. Both nanoparticles were suspended in ethanolic medium. Electrophoretic deposition parameters were optimized. The results show that an applied voltage of 5 V, was suitable to be used to deposit single layer of MUA capped CdSe, TiO2 nanoparticles and the mixture of MUA capped CdSe-TiO2 nanoparticles. Smooth, uniform and dense layer were produced under this applied voltage. EPD also allows deposition of multilayer structures, in this research two layer structures of MUA capped CdSe on electrophoretically deposited TiO2 on FTO and mixed MUA capped CdSe-TiO2 on electrophoretically deposited TiO2 on FTO were formed. Three layer structures of MUA capped CdSe/MUA capped CdSe-TiO2/ TiO2/FTO were also synthesised. The photocurrent was measured on single layer, two layer and three layers electrodes. The optimum photocurrent parameters for each single layer were studied, in order to measure the photocurrent at the best condition possible. The highest IPCE value recorder was 0.70 % on MUA capped CdSe on FTO, with the MUA capped CdSe size of 2.94 nm. The lowest IPCE, 0.011 %, was obtained from three layer structure of MUA capped CdSe/MUA capped CdSe-TiO2/ TiO2/FTO.
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Bair, Nathan A. "Synthesis and Characterization of an Oligothiophene-Ruthenium Complex and Synthesis and Optical Properties of Oligothiophene-Ruthenium Complexes Bound to CdSe Nanoparticles." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2596.
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Oligothiophenes are of increasing interest in organic based electronic devices in part due to their high electron and hole mobilities. In an organic photovoltaic (OPV) device, the electronic properties of oligothiophenes make them advantageous as charge transfer junctions. To serve as charge transfer junctions, oligothiophenes must be functionalized to bind to the donor and acceptor parts of the device. The donor and acceptor parts are different materials and the synthesis of asymmetric oligothiophenes is of great interest. Previous researchers in our lab synthesized four asymmetric oligothiophenes, two with two thiophene subunits and two with four. Each set of oligothiophenes contained a pair of constitutional isomers. Here we report the synthesis of another asymmetric oligothiophene, one with three thiophene subunits. This compound is functionalized with bipyridine to bind Ru(bpy)22+ and with phosphonic acid moieties to bind CdSe nanoparticles. The synthesis was carried out by bonding a phosphonic acid moiety to bithiophene and bipyridine to thiophene and then coupling the phosphate-bithiophene and thiophene-bipyridine. Standard Stille couplings were used for carbon-carbon bond formation. The resulting compounds have complex NMR spectra and overlapping Ru MLCT and π-π* transitions at 450 nm with molar extinction coefficient on the order of 3 x 105 M-1 cm-1. The thiophene fluorescence is quenched by Ru(bpy)22+. These optical properties compare closely with the previous compounds synthesized. Solar cells occupy significant attention in the media, politics and science for their promise of continual pollution-free energy. Quantum dots, metal complexes and organic compounds are all under research as viable replacements for expensive silicon solar cells. To test the efficacy of a light harvesting compound before constructing a solar cell, a model system is constructed to show electron transfer from the light harvester into an electron acceptor. We synthesized oligothiophenes and oligothiophene-ruthenium complexes and tested their ability to act as sensitizers and charge transfer junctions. To do this, they were bonded to CdSe nanoparticles and their optical properties were measured. Steady-state photoluminescence and time correlated single photon counting were used to observe the effects on fluorescence and fluorescence lifetime of the CdSe-oligothiophene and CdSe-oligothiophene-ruthenium complexes before and after binding. It was found that CdSe fluorescence was quenched when bound to an oligothiophene ruthenium complex, and that the fluorescence of the oligothiophene was quenched when bound to CdSe in the absence of ruthenium. The fluorescence lifetimes of the quenched species were shortened.
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Dickerson, Bryan Douglas. "Organometallic Synthesis Kinetics of CdSe Quantum Dots." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27322.
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CdSe quantum dots produced by organometallic synthesis are useful as tunable emitters for photonic devices and as multi-colored protein markers for biomedical imaging, applications requiring bright and narrow emission. A diffusion-limited model helped monitor growth rates via photoluminescence and absorbance spectroscopy, in order to characterize synthesis kinetics in stearic acid, dodecylamine, and in trioctylphosphine oxide. The nucleation rate increased with Se concentration, while the growth rate followed the Cd concentration.
Emission peak widths, emission redshift rates, nanocrystal growth rates, and reactant concentrations all decreased to a minimum when emission reached the critical wavelength, at a reaction completion time, tc. The temperature dependence of 1/tc and of redshift rates followed Arrhenius behavior governed by activation energies, which were tailored by the choice of solvent. Synthesis in solvents, such as stearic acid, with lower activation energies produced faster initial nanocrystal growth and longer critical wavelengths. The highest photoluminescence quantum yield was generally at wavelengths shorter than the critical wavelength, when moderate growth rates enabled surface reconstruction while precursors were still available.Ph. D.
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Herz, Erik. "Colloidal Semiconductor Nanocrystals: A Study of the Syntheses of and Capping Structures for CdSe." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/10147.
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Luminescent quantum dots (QDs) or rods are semiconductor nano-particles that may be used for a wide array of applications such as in electro-optical devices, spectral bar coding, tagging and light filtering. In the case under investigation, the nano-particles are cadmium-selenide (CdSe), though they can be made from cadmium-sulfide, cadmium-telluride or a number of other II-VI and III-V material combinations. The CdSe quantum dots emit visible light at a repeatable wavelength when excited by an ultraviolet source. The synthesis of colloidal quantum dot nanoparticles is usually an organo-metallic precursor, high temperature, solvent based, airless chemical procedure that begins with the raw materials CdO, a high boiling point ligand, and a Se-trioctylphosphine conjugate. This investigation explores the means to produce quantum dots by this method and to activate the surface or modify the reaction chemistry with such molecules as trioctylphosphine oxide, stearic acid, dodecylamine, phenyl sulfone, aminophenyl sulfone, 4,4'dichlorodiphenyl sulfone, 4,4'difluorodiphenyl sulfone, sulfanilamide and zinc sulfide during the production to allow for further applications of quantum dots involving new chemistries of the outer surface. Overall, the project has been an interesting and successful one, producing a piece of equipment, a lot of ideas, and many dots with varied capping structures that have been purified, characterized, and stored in such a way that they are ready for immediate use in future projects.Master of Science
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Vannoy, Charles Harvey. "Behavioral Effects of Functionalized CdSe/ZnS Quantum Dots in Self-Organization and Protein Fibrillation." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/431.
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Advances in recent nanoscience technologies have generated a new compilation of biocompatible, fluorescent nanoparticles derived from semiconductor quantum dots (QDs). QDs are extremely small in size and possess very large surface areas, which gives them unique physical properties and applications distinct from those of bulk systems. When exposed to biological fluid, these QDs may become coated with proteins and other biomolecules given their dynamic nature. These protein-QD systems may affect or enhance the changes in protein structure and stability, leading to the destruction of biological function. It is believed that these QDs can act as nucleation centers and subsequently promote protein fibril formation. Protein fibrillation is closely associated with many fatal human diseases, including neurodegenerative diseases and a variety of systemic amyloidoses. This topic of protein-QD interaction brings about many key issues and concerns, especially with respect to the potential risks to human health and the environment. Herein, the behavioral effects of dihydrolipoic acid (DHLA)-capped CdSe/ZnS (core/shell) QDs in hen egg-white lysozyme (HEWL) and human serum albumin (HSA) protein systems were systematically analyzed. This study gives rise to a better understanding of the potentially useful application of these protein-QD systems in nanobiotechnology and nanomedicine as a bioimaging tool and/or as a reference for controlled biological self-assembly processes.
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Zane, Andrew Paul. "The Synthesis and Behavior of Positive and Negatively Charged Quantum Dots." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316472706.
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Salverson, Lynsey Alexandra-McLennan. "An Engineering Approach Investigating the Uptake and Phytotoxicity of One Type of Engineered Nanoparticle (CdSe/ZnS Quantum Dots) by Solanum lycopersicum." Digital Commons at Loyola Marymount University and Loyola Law School, 2012. https://digitalcommons.lmu.edu/etd/42.
Full textAbstract:
The novel and extraordinary physiochemical properties of engineered nanoparticles (ENPs) are certain; however, their unique characteristics raise growing concerns regarding potentially adverse effects on biological and ecological systems. It is becoming increasingly evident that, before the full potential of nanotechnology can be realized, standardized characterization of ENP behavior, fate, and effects on the ecosystem are essential to ensure the safe manufacturing and use of ENP products. Otherwise, the promise of such extraordinary advancements may find itself limited to applications such as electronics and sporting equipment, industries in which ENPs currently reside. The current toxicity profile of engineered nanomaterials is not only preliminary, but highly variable amongst researchers. Consequently, there is great need for the development of a highly organized, efficient, and precise approach to assess the hazardous potential ENPs may pose, while addressing the safety concerns surrounding and limiting nanotechnology. In response to such concerns, the present study took an engineering approach, in an otherwise traditionally viewed discipline, to assess the potential impact of one type of engineered nanoparticle, water-soluble (MUA) CdSe/ZnS- quantum dots (QDs), on tomato (Solanum lycopersicum) seedlings, by implementing a full factorial design of experiment (FDOE), in an effort to identify which factors, and their interactions, have a significant (p ≤ 0.05) effect on root and shoot elongation, and if any observed effects are a result of particle uptake, evaluated via fluorescence microscopy imaging. By implementing factorial experimental design methodologies, not only are we efficiently identifying the factors that affect phytotoxicity, we are providing, for the first time to our knowledge, the first scientific data to report the significant interaction effects between the factors responsible for ENP toxicity. (MUA) CdSe/ZnS quantum dots had a negative influence on root and shoot lengths of tomato seedlings exposed for 3 days, as well as those exposed for 6 days. The observed influence depended on QD concentration and exposure time, as statistical analyses found QD concentration, exposure time, and the concentration-exposure time interaction significantly (p ≤ 0.05) affected root and shoot lengths of tomato seedlings. Additionally, to minimize the observed phytotoxicity effects (i.e., to maximize tomato root lengths), our results suggest that exposure of tomato seeds to low QD concentration levels (125 mg/L) for short periods of time (maximum of 3 days) to yield maximum root lengths of approximately 2.21 cm, that is – minimal phytotoxicity effects.
Books on the topic "CdSe nanoparticle"
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Schiener, Andreas. Mikrosekundenaufgelöste In-situ-SAXS-Experimente zum Nukleations- und Wachstumsverhalten von CdS-Nanopartikeln in wässriger Lösung. Erlangen: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2017.
Find full textBook chapters on the topic "CdSe nanoparticle"
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Patra, S. R., and B. Mallick. "X-Ray Probing for the Structural and Functional Studies of CdSe-CdS Nanoparticle for Detector Application." In Materials Horizons: From Nature to Nanomaterials, 297–314. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-8391-6_15.
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Nikolopoulos, D., I. Valais, Panayotis H. Yannakopoulos, C. Michail, C. Fountzoula, A. Bakas, I. Kandarakis, and G. Panayiotakis. "Luminescence Efficiency of Cadmium Selenide/Zinc Sulfide (CdSe/ZnS) Quantum Dot Nanoparticle Sensors Under X-Ray Excitation." In NATO Science for Peace and Security Series B: Physics and Biophysics, 53–59. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-017-7468-0_5.
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Nosaka, Y. "Electronic States of Chemically Modified CdS Nanoparticles." In Single Organic Nanoparticles, 253–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55545-9_20.
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Pan, B. F., R. He, F. Gao, L. M. Ao, H. Y. Tian, and D. X. Cui. "Growth Kinetics of CdSe Nanoparticles in Lauric Acid." In Solid State Phenomena, 139–44. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/3-908451-30-2.139.
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Park, Yeon-Su, Yukihiro Okamoto, Noritada Kaji, Manabu Tokeshi, and Yoshinobu Baba. "Size-Selective Synthesis of Ultrasmall Hydrophilic CdSe Nanoparticles in Aqueous Solution at Room Temperature." In Nanoparticles in Biology and Medicine, 125–41. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-953-2_9.
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Vishwakarma, Kirti, O. P. Vishwakarma, and S. K. Pandey. "Photoluminescence Studies of CdS Nanoparticles." In Proceedings of All India Seminar on Biomedical Engineering 2012 (AISOBE 2012), 83–86. India: Springer India, 2012. http://dx.doi.org/10.1007/978-81-322-0970-6_10.
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Nakamura, Hiroyuki, Masaya Miyazaki, Hideaki Maeda, Asuka Tashiro, Kazuya Ogino, and Takanori Watari. "CdSe nanoparticles formation in a microspace and their properties." In Micro Total Analysis Systems 2002, 885–87. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0504-3_95.
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Gérard, Valérie A., Yurii K. Gun’ko, Babu R. Prasad, and Yury Rochev. "Synthesis of Biocompatible Gelatinated Thioglycolic Acid-Capped CdTe Quantum Dots (“Jelly Dots”)." In Nanoparticles in Biology and Medicine, 275–81. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-953-2_21.
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Miguel, Ana Sofia, Christopher Maycock, and Abel Oliva. "Synthesis and Functionalization of CdSe/ZnS QDs Using the Successive Ion Layer Adsorption Reaction and Mercaptopropionic Acid Phase Transfer Methods." In Nanoparticles in Biology and Medicine, 143–55. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-953-2_10.
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Sung, Myoung Seok, Yoon Bok Lee, Young Seok Kim, Young Mok Rhyim, Jin Chun Kim, In Bae Kim, and Yang Do Kim. "Preparation and Characterization of CdSe Nanoparticles Prepared by Using Ultrasonic Irradiation." In Key Engineering Materials, 2034–36. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-410-3.2034.
Full textConference papers on the topic "CdSe nanoparticle"
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Philipp, G. "CdSe nanoparticle arrays contacted on electron transparent substrates." In The 14th international winterschool on electronic properties of novel materials - molecular nanostructures. AIP, 2000. http://dx.doi.org/10.1063/1.1342550.
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Nikdoost, Arsalan, Alican Ozkan, Yusuf Kelestemur, Hilmi Volkan Demir, and E. Yegan Erdem. "Silica Nanoparticle Formation by Using Droplet-Based Microreactor." In ASME 2017 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2017 Conference on Information Storage and Processing Systems. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/ipack2017-74178.
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This paper describes a method for the synthesis of silica nanoparticles that can be later used for coating of quantum dots inside a microfluidic reactor. Here, a droplet-based system is used where two reagents were mixed inside the droplets to obtain silica. Particles in the size range of 25±2.7 nm were obtained with comparable size distribution to controlled batch-wise synthesis methods. This method is suitable to be used later to coat CdSe nanoparticles inside the microreactor.
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Son, Taehwang, Saji Thomas Kochuveedu, Dong Ha Kim, and Donghyun Kim. "Near-field analysis of CdSe quantum dot conjugated core-shell nanoparticle." In SPIE BiOS, edited by Alexander N. Cartwright and Dan V. Nicolau. SPIE, 2014. http://dx.doi.org/10.1117/12.2038885.
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Park, Inkyu, Seung H. Ko, Heng Pan, Albert P. Pisano, and Costas P. Grigoropoulos. "Micro/Nanoscale Structure Fabrication by Direct Nanoimprinting of Metallic and Semiconducting Nanoparticles." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43878.
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In this paper, we present our recent development of direct nanoimprinting of metal and semiconductor nanoparticles for a simple but high-throughput fabrication of micro/nanoscale structures. Nanoparticle suspension with self-assembled-monolayer (SAM) protected-nanoparticles (Au, Ag, and CdSe-ZnS core-shell quantum dots) suspended in alpha-terpineol carrier solvent are used as solutions for direct nanoimprinting. Polydimethylsiloxane (PDMS)-based soft imprinting molds with micro/nanoscale features are used. Process and material flexibility enable a very low temperature (80°C) and low pressure (5psi) nanoimprinting process and results in superfine features from micrometers down to ∼100nm resolutions. We will show the geometrical and electrical characterization of nanoimprinted structures and demonstrate working electronic components such as resistors or organic field effect transistors (OFET).
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Lasne, D., L. Cognet, S. Berciaud, G. A. Blab, L. Groc, M. Heine, D. Choquet, and B. Lounis. "Single molecule CdSe/ZnS quantum dot and gold nanoparticle detection in live neurons." In Biomedical Optics 2006, edited by Marek Osinski, Kenji Yamamoto, and Thomas M. Jovin. SPIE, 2006. http://dx.doi.org/10.1117/12.647788.
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KULAKOVICH, O. S., A. V. MEDVEDZ, A. A. MASKEVICH, S. A. MASKEVICH, and N. D. STREKAL. "PHOTOLUMINESCENCE OF PHYSI- AND CHEMISORBED CdSe/ZnS NANOPARTICLE SUBMONOLAYERS ON THE SILANATED GLASS." In Reviews and Short Notes to Nanomeeting-2005. WORLD SCIENTIFIC, 2005. http://dx.doi.org/10.1142/9789812701947_0032.
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Salverson, Lynsey A. M., Nader Saniei, Mel Mendelson, and Michelle Lum. "An Engineering Approach Investigating the Uptake and Phytotoxicity of One Type of Engineered Nanoparticle (CdSe/ZnS Quantum Dots) by Solanum Lycopersicum." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14032.
Full textAbstract:
The novel and extraordinary physiochemical properties of engineered nanoparticles (ENPs) is certain, yet, at the same time, their unique characteristics raise growing concerns regarding potentially adverse effects on biological and ecological systems. It is becoming increasingly evident, that before the full potential of nanotechnology can be realized, standardized characterization of ENPs behavior, fate, and their effects in the ecosystem are essential, to ensure the safe manufacturing and use of ENP products. Otherwise, the promise of such extraordinary advancements may find itself limited to applications such as electronics, and sporting equipments, industries in which it currently resides. The current toxicity profile of engineered nanomaterials is not only preliminary, but highly variable amongst researchers. Emphasizing the great need to develop a highly organized, efficient, and precise approach to assess the hazardous potential ENPs may pose, and address the safety concerns surrounding and limiting nanotechnology. In response to such concerns, the present study took an engineering approach, in an otherwise traditionally viewed discipline, to assess the potential impact of engineered nanoparticles on tomato (Solanum lycopersicum) seedlings, by implementing a full factorial design of experiment (FDOE) in an effort to identify what factors, and their interactions, have a significant (p ≤ 0.05) effect on root and shoot elongation, and if any observed effects are a result of particle uptake, evaluated via fluorescence microscopy imaging. Therefore, the goal of our study was to design and implement an efficient, effective, and precise method to assess the effect of one type of ENP, water-soluble CdSe/ZnS quantum dots, using Solanum lycopersicum as our model organism, one of 10 species recommended by the Unites States Environmental Protection Agency (US EPA) for use in phytotoxicity studies, via a methodology we believe novel to nanotechnology. By implementing factorial experimental design methodologies, not only are we efficiently identifying the factors that affect phytotoxicity, we are providing, for the first time to our knowledge, the first scientific data to report the significant interaction effects between the factors responsible for ENP toxicity. Water soluble (MUA) CdSe/ZnS quantum dots used in our study had a negative influence on root and shoot lengths of tomato seeds exposed for 3 and 6 days. The observed influence depended on (MUA) CdSe/ZnS concentration and QD exposure time. The importance of the factor effects were examined via analysis of variance (ANOVA), t-tests, confidence intervals, and normal plot statistical analyses. The findings concluded that factors B, C, and the BC-interaction (CdSe/ZnS: Exposure time, concentration, and exposure time–concentration interaction) significantly (p ≤ 0.05) affected root and shoot lengths of tomato seedlings. Thus, factors A, AB, AC, and ABC (CdSe/ZnS QD: Size, size–concentration, size-exposure time, and size-concentration-exposure time interactions) were not found to have a significant effect on root and shoot lengths of tomato seedlings, and ultimately eliminated from our model. After analyzing the interaction plots, it became evident that low percentages of root reduction are obtained at low concentration levels for short lengths of time; thus, to obtain the least amount of phytotoxic effects one would set factors B (concentration) and C (exposure time) to their low levels, 125 mg/L for 3 days, respectively. Alternatively, high percentages of root reduction are obtained at high concentration levels for long lengths of time; thus, to obtain the greatest phytotoxic effect one would set factors B and C to their high levels, 1000 mg/L for 6 days, respectively. This indicates that as exposure time increases, root reduction increases; thus, phytotoxicity increases. Since our study attempted to realize which factors minimize phytotoxicity effects of one type of ENP, these findings suggest that to minimize phytotoxicity effects (i.e. maximize root length or minimize percent of root reduction) of (MUA) CdSe/ZnS QDs on tomato seeds, set factors B and C (QD concentration and exposure time) to their low levels; that is, expose tomato seeds to 125 mg/L of QD solution for a maximum of 3 days. These settings will yield the least amount of root reduction (5.15%) and; thus, phytotoxicity effects will be minimized. With regard to tomato roots ability to uptake MUA QDs, our results contribute to the literature by reporting uptake possible. Although we did see particles inside the root, it was sporadic and difficult to quantify. As to whether it was intracellular (within the cell) or intercellular (in the spaces between the cells, i.e., outside the cells) we could not conclude with certainty, although we suspect the QDs were intercellular. Thus, we highly recommend future experiments involving cross sections and more in-depth microscopy imaging. Additionally, although the results of our experiment failed to support that particle size (t = 2.13; d.f. = 1; p = 0.065) or the particle size-exposure time interaction (t = 2.17; d.f. = 1; p = 0.062) had a significant effect on root and shoot lengths of tomato seedlings, due to the small p-value associated with both test statistics, it is our belief that particle size and the particle size-exposure time interaction may, in fact, be a real effect; thus, further investigation is recommended.
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Sukanya, D., and P. Sagayaraj. "A simple and facile synthesis of MPA capped CdSe and CdSe/CdS core/shell nanoparticles." In NANOFORUM 2014. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4917669.
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Prabhu, M., V. S. Manikandan, N. Soundararajan, and K. Ramachandran. "Ethanol gas sensing by Zn-doped CdS/CdTe nanoparticles." In DAE SOLID STATE PHYSICS SYMPOSIUM 2015. Author(s), 2016. http://dx.doi.org/10.1063/1.4947795.
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Deng, Dawei, and Yueqing Gu. "Spontaneous transition and concomitant self-assembly of CdTe nanoparticles into CdS nanosheets induced by L-cysteine." In Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications. SPIE, 2009. http://dx.doi.org/10.1117/12.807358.
Full textReports on the topic "CdSe nanoparticle"
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NREL Improves Hole Transport in Sensitized CdS-NiO Nanoparticle Photocathodes (Fact Sheet). Office of Scientific and Technical Information (OSTI), January 2012. http://dx.doi.org/10.2172/1033818.
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