Dissertations / Theses on the topic 'InP/ZnS quantum dots'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'InP/ZnS quantum dots.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Carlini, Lina. "Photosensitization of InP/ZnS quantum dots for photodynamic therapy." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106430.
Full textLa thérapie photodynamique (TPD) est un traitement médical qui détruit les cellules cancéreuses en utilisant des photons de lumière, typiquement en forme de laser, afin d'activer des drogues photosensibles. Présentement, les médicaments approuvés pour usage clinique ont d'importantes limitations. Particulièrement, le coefficient d'absorption des tissus humains se retrouve dans la même gamme de longueur d'onde où les médicaments sont excitables; par conséquent, leur efficacité est compromise. Les nanoparticules de matériaux semi-conducteurs, appelées aussi points quantiques (PQs), ont l'habilité de surpasser cette limitation parce qu'ils peuvent être produits pour absorber la lumière à n'importe quelle longueur d'onde. L'objectif de cette thèse est donc d'évaluer la possibilité d'utiliser les PQs pour la TPD. Plus spécifiquement, les PQs composés d'un cœur de phosphure d'indium (InP) avec une coquille du sulfure de zinc (ZnS) ont été examinés. La spectroscopie par résonance paramagnétique électronique (RPE) et les tests colorimétriques ont été utilisés pour identifier la nature des espèces toxiques produites, ainsi que le mécanisme responsable de leur formation. Les résultats ont montré que les particules de InP/ZnS produisent des anions de superoxyde et des radicaux d'hydroxyle; la quantité des radicaux formés dépend de l'épaisseur de la coquille ZnS. En plus, la microscopie confocale a été utilisée pour évaluer l'ingestion intracellulaire des PQs par divers types de cellules. Ces images ont démontré que les PQs se concentrent dans le cytoplasme autour du noyau et que les cellules mélanomes de type B16 sont celles qui absorbent le plus (2.5 fois plus que les cellules KB). Finalement, les PQs ont été conjuguées à un agent chimiothérapeutique (doxorubicin (Dox)) et leur toxicité a été explorée par cytométrie en flux et des tests colorimétriques. La mort cellulaire a augmenté avec l'attachement de PQs, ce qui s'explique par une amélioration de la livraison intracellulaire de Dox. En conclusion, les PQs InP/Zn révèlent être des candidats prometteurs en tant que médicaments et agents de livraison pour la TPD, cependant certains éléments de leur structure restent à être améliorés.
Panzer, Rene, Chris Guhrenz, Danny Haubold, Rene Hübner, Nikolai Gaponik, Alexander Eychmüller, and Jan J. Weigand. "Tri(pyrazolyl)phosphane als Phosphorpräkursoren für die Synthese von hochemittierenden InP/ZnS Quantenpunkten." Technische Universität Dresden, 2018. https://tud.qucosa.de/id/qucosa%3A31166.
Full textPanzer, Rene, Chris Guhrenz, Danny Haubold, Rene Hübner, Nikolai Gaponik, Alexander Eychmüller, and Jan J. Weigand. "Versatile Tri(pyrazolyl)phosphanes – Application as phosphorus precursors for the synthesis of highly emitting InP/ZnS quantum dots." Technische Universität Dresden, 2018. https://tud.qucosa.de/id/qucosa%3A31156.
Full textAlbahrani, Sayed Mohamed Baqer. "Photoluminescent CdSe/CdS/ZnS quantum dots for temperature and pressure sensing in elastohydrodynamic." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI016/document.
Full textTemperature and pressure are two relevant parameters for the optimization of lubrication performance in the elastohydrodynamic lubrication (EHL) regime. To date, various experimental methods have been developed to measure these two parameters with more or less success. In a continuation of these efforts, some investigations are presented in the current work in view of developing a new in situ technique allowing for local measurements of these two parameters throughout elastohydrodynamic (EHD) contacts. This technique exploits the photoluminescence (PL) sensitivity of CdSe/CdS/ZnS quantum dots (QDs) to changes in temperature and pressure. In this respect, calibrations have been carried out in order to establish the sensitivity of these QDs to the two parameters. Moreover, the versatility of these QDs for sensing applications have been examined by testing two different lubricants, namely squalane and a mixture of squalane and cyclopentane. Some measurements were also conducted under dynamic conditions, in order to study (i) the influence of the QDs presence on the lubricant rheology and (ii) the influence of shear rate on the PL of QDs. Although these different tests demonstrated the potential of CdSe/CdS/ZnS QDs, they revealed the existence of other parameters that affect, in addition to temperature and pressure, their response. A comprehensive study was thus conducted in order to elucidate the mechanisms behind these findings. More importantly, a methodology was defined in order to minimize these undesired influences and, in fine, enable these QDs to be used as reliable nanosensors
Virieux, Heloise. "Nanocristaux luminescents de phosphures d'indium et de zinc : synthèse, enrobage et caractérisation." Thesis, Toulouse, INSA, 2013. http://www.theses.fr/2013ISAT0030/document.
Full textRésumé de la thèse en anglais : This PhD investigation focuses on organometallic synthesis of indium phosphide (InP), zinc phosphide (Zn3P2) colloidal semiconductor nanoparticles (NPs) and core/shell structures which were obtained by the growth of a layer of zinc sulfide (ZnS) on the surface. The objectives are to understand and control the synthesis in order to shift the absorption and emission wavelengths to the near infra-red range, interesting for biomedical imaging.The first chapter presents the state of the art on the InP and InP/ZnS nanocrystals (NCx). A brief recall on the physical and chemical properties of semiconductor NCx is presented and various syntheses are described. Particular attention was paid to the size of NCx, the shift of the fluorescence emission to higher wavelengths and the optimization of quantum yields. The potential of these objects for white light emitting diodes (LED) or biomedical imaging shows the value added of using InP/ZnS NCx rather than other materials based on toxic elements such as cadmium, lead elements…The second chapter focuses on a synthesis from indium carboxylates known in the literature. The goal is to characterize the structure of NPs to understand the procedure of the synthesis and the coating. Measurements by Nuclear Magnetic Resonance (NMR) in solid state and Photoelectronic X-ray spectroscopy (XPS) revealed the oxidation of InP of the NPs. This oxide layer increases during the coating. This originates from a decarboxylating coupling of carboxylic acids at high temperature in the presence of NPs. This oxidation is believed to inhibit the growth of the object, which restricts the attainable range of wavelengths.The third chapter provides a novel synthesis from indium amidinate instead of indium carboxylate. The advantage of this approach is the potential to lower significantly the reaction temperature (150°C instead of 280°C) and to avoid secondary decarboxylation reaction. A coating with ZnS at low temperature (150°C) is also developed. The synthesis of InP NPs also causes an oxidation of the surface. A coupling takes place again between the ligands, palmitic acid and hexadecylamine providing new oxidizing conditions. The study of different ratios of ligands shows that when the reaction medium is modified, the InP NPs do not exhibit a conclusive luminescence response. Synthesis and coating are carried out under an atmosphere of hydrogen (H2) in Fisher-Porter reactor in order to counter these oxidizing conditions. NPs with diameters of the order of 3,4 nm (a necessary condition to approach the infra-red emission) and a quantum yield of 18-20% are thus obtained. These had never been observed before during this thesis.The last chapter is devoted to an exploratory study on Zn3P2 NPs. Zinc phosphide is a promising material because of non-toxic and abundant constituents, and potential access to near infra-red wavelengths. Different synthesis parameters are studied and the structural and optical properties are characterized. Preliminary results on the coating show instabilities of the Zn3P2 NPs. The use of trioctylphoshine oxide (TOPO) appears to allow the passivation of the NPs in the air and a better stability is possible under an atmosphere of H2
Boonkoom, Thitikorn. "InP quantum dots for hybrid photovoltaic devices." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/17778.
Full textWinzell, Ann. "Surface Modification of CdSe(ZnS) quantum dots for biomedical applications." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-56022.
Full textQuantum dots are inorganic nanocrystals of semiconductor metals that have unique light emitting properties. Due to their tunable and narrow emission profile, broad absorption spectra, resistance to photobleaching and high level of brightness they have emerged as inorganic fluorophores and numerous applicabilities for in vitro, in situ as well as in vivo studies are present. The chemical nature of the quantum dot surface needs to be altered in order to make the inorganic nanoparticles applicable to biological systems. Water soluble and biocompatible particles that limit unspecific binding to proteins can be obtained through functionalization of the surface coating with appropriate molecules.
In this pilot study, two surface modification strategies were performed upon two commercially available quantum dots in order to attach the zwitterionic molecules L-cysteine and thiolated sulfobetaine methacrylate, both shown to create non-fouling and biocompatible surfaces.
A biphasic exchange method was successfully used to perform ligand exchange of Qdot® ITK™ Organic Quantum Dots (QD-Organic) in order to exchange the structurally unknown, native lipophilic coating to one consisting of the amino acid L-cysteine (QD-Cysteine). The quantum dots transferred from the organic to the aqueous phase after the natively hydrophobic coating was changed to the hydrophilic L-cysteine. A characteristic mass fragment of protonated trioctylphosphine oxide (TOPO) was found for QD-Organic, using TOF-SIMS, suggesting TOPO is a part of the native coating. Further, the mentioned mass fragment was no longer present after the exchange. The C (1s) XPS-spectrum showed a new peak for carboxylic carbon, characteristic for L-cysteine, and expected changes in elemental composition were consistent with measured changes for all relevant elements. Large amounts of buffer remained after purification, suggesting the purification protocol needs further evaluation. Traces of the native coating were found in the C (1s) XPS-spectrum for QD-Cysteine, indicating not all ligands were exchange.
Additionally, a strategy for surface functionalization of Qdot® 655 ITK™ amino (PEG) quantum dots (QD-PEG-NH2) with L-cysteine and thiolated sulfobetaine methacrylate was outlined and performed, using Michael addition and the heterobifunctional linker 3-Maleimidobenzoic acid N-hydroxysuccinimide ester. Unfortunately, no indications of successful attachment of the linker to the quantum dot have been found, neither by TOF-SIMS nor XPS, and thus functionalization with L-cysteine and tSBMA was not achieved. In theory, the proposed coupling chemistry used during the pilot study is promising, but further experiments are needed to obtain a successful and optimized protocol for the functionalization.
Cheriton, Ross. "Electrostatic Control of Single InAs Quantum Dots Using InP Nanotemplates." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22758.
Full textKors, Andrei [Verfasser]. "InP - based quantum dots for telecom wavelengths ranges / Andrei Kors." Kassel : Universitätsbibliothek Kassel, 2020. http://d-nb.info/1222555239/34.
Full textAngell, Joshua James. "SYNTHESIS AND CHARACTERIZATION OF CdSe-ZnS CORE-SHELL QUANTUM DOTS FOR INCREASED QUANTUM YIELD." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/594.
Full textQejvanaj, Fatjon. "Correlation of size and photoluminescence of single CdSe/ZnS quantum dots." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99562.
Full textBryan, Caroline. "Optical and structural characterisation of InP based quantum wells and dots." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/7276.
Full textCoe-Sullivan, Seth (Seth Alexander). "Efficient light emitting devices utilizing CdSe(ZnS) quantum dots in organic host matrices." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/28354.
Full textIncludes bibliographical references (leaves 29-32).
We demonstrate efficient electroluminescence from thin film structures containing core-shell CdSe(ZnS) quantum dots dispersed in molecular organic host materials. In the most efficient devices, excitons are created on the quantum dot sites via energy transfer from organic host molecules, and direct charge injection into the quantum dots is minimized. For quantum dots with core diameter 38 [Angstroms], the electroluminescence spectra peak at 562nm and have full width at half maximum as narrow as 32nm. Saturated color devices have external quantum efficiencies as high as 0.61% at the current density of 7mA/cm². At 125mA/cm², the device luminance is 1900cd/m², which corresponds to a luminescence efficiency of 1.5 cd/A. The yield over hundreds of devices is greater than 90%, indicating a robust material system.
by Seth Alexander Coe.
S.M.
Hatami, Fariba. "Indium phosphide quantum dots in GaP and in In 0.48 Ga 0.52 P." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2002. http://dx.doi.org/10.18452/14873.
Full textThe growth and structural properties of self-assembled InP quantum dots are presented and discussed, together with their optical properties and associated carrier dynamics. The QDs are grown using gas-source molecular-beam epitaxy in and on the two materials InGaP (lattice matched to GaAs) and GaP. Under the proper growth conditions, formation of InP dots via the Stranski-Krastanow mechanism is observed. The critical InP coverage for 2D-3D transition is found to be 3ML for the InP/ InGaP system and 1.8ML for the InP/GaP system. The structural characterization indicates that the InP/GaP QDs are larger and, consequently, less dense compared to the InP/ InGaP QDs; hence, InP dots on GaP tend to be strain-relaxed. The InP/ InGaP QDs tend to form ordered arrays when InP coverage is increased. Intense photoluminescence from InP quantum dots in both material systems is observed. The PL from InP/GaP QDs peaks between 1.9 and 2 eV and is by about 200 meV higher in energy than the PL line from InP/ InGaP QDs. The optical emission from dots is attributed to direct transitions between the electrons and heavy-holes confined in the InP dots, whereas the photoluminescence from a two-dimensional InP layer embedded in GaP is explained as resulting from the spatially indirect recombination of electrons from the GaP X valleys with holes in InP and their phonon replicas. The type-II band alignment of InP/GaP two-dimensional structures is further confirmed by the carrier lifetime above 19 ns, which is much higher than in type-I systems. The observed carrier lifetimes of 100-500 ps for InP/ InGaPQDs and 2 ns for InP/GaP QDs support our band alignment modeling. Pressure-dependent photoluminescence measurements provide further evidence for a type-I band alignment for InP/GaP QDs at normal pressure, but indicate that they become type-II under hydrostatic pressures of about 1.2 GPa and are consistent with an energy difference between the lowest InP and GaP states of about 31 meV. Exploiting the visible direct-bandgap transition in the GaP system could lead to an increased efficiency of light emission in GaP-based light emitters.
Katmis, Asli Ugur. "Growth and characterization of InP/In0.48Ga0.52P quantum dots optimized for single-photon emission." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16696.
Full textIn this work the growth of self-assembled InP/InGaP quantum dots, as well as their optical and structural properties are presented and discussed. The QDs were grown on InGaP, lattice matched to GaAs.Self-assembled InP quantum dots are grown using gas-source molecular beam epitaxy over a wide range of InP deposition rates, using an ultra-low growth rate of about 0.01 atomic monolayers/s, a quantum-dot density of 1 dot/μm2 is realized. The resulting isolated InP quantum dots are individually characterized without the need for lithographical patterning and masks on the substrate. Both excitionic and biexcitonic emissions are observed from single dots, appearing as doublets with a fine-structure splitting of 320 μeV. Hanbury Brown-Twiss correlation measurements for the excitonic emission under cw excitation show anti-bunching behavior with an autocorrelation value of g(2)(0)=0.2. This system is applicable as a single-photon source for applications such as quantum cryptography. The formation of well-ordered chains of InP quantum dots on GaAs (001) substrates by using self-organized InGaP surface undulations as a template is also demonstrated. The ordering requires neither stacked layers of quantum dots nor substrate misorientation. The structures are investigated by polarization-dependent photoluminescence together with transmission electron microscopy. Luminescence from the InGaP matrix is polarized in one crystallographic direction due to anisotropic strain arising from a lateral compositional modulation. The photoluminescence measurements show enhanced linear polarization in the alignment direction of quantum dots, [-110]. A polarization degree of 66% is observed. The optical anisotropy is achieved with a straightforward heterostructure, requiring only a single layer of QDs.
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.
Full textVeloso, Aline Bessa. "Propriedades ópticas de pontos quânticos empilhados de InP/GaAs." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277760.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
Made available in DSpace on 2018-08-09T11:09:31Z (GMT). No. of bitstreams: 1 Veloso_AlineBessa_M.pdf: 2273008 bytes, checksum: 19cf5ce00aebec12cc1795518a811244 (MD5) Previous issue date: 2007
Resumo: Nesta dissertação, estudamos as propriedades ópticas e estruturais de pontos quânticos (QDs) empilhados de InP/GaAs, crescidos por método de auto-formação, conhecido como o modo Stranskii-Krastanov, em um sistema de epitaxia por feixe químico. Os pontos quânticos de InP/GaAs possuem alinhamento das bandas tipo-II nas interfaces, onde somente o elétron fica confinado no QD, enquanto o buraco fica localizado em volta dele na camada de GaAs atraído pelo elétron. Investigamos amostras com diferentes separação d entre duas camadas de QDs de InP, variando de 3 a 12 nm. As análises estruturais foram feitas por técnica microscopia eletrônica de transmissão (TEM) e as análises ópticas por fotoluminescência de feixe contínuo (PL-CW) e de resolvida no tempo (PL-RT) com a temperatura variando de 2 a 120 K. As imagens de TEM mostram alinhamento vertical dos QDs e maiores tamanhos para os que estão na segunda camada. As medidas de PL-CW, a baixas temperaturas, apresentam largura de linha da banda de emissão mais estreita e simétrica nas amostras de QDs empilhados do que a de amostra de uma camada simples. Isso é atribuído à maior uniformidade de tamanhos de QDs da segunda camada. Atribuímos aos efeitos de acoplamento quântico e de tunelamento dos portadores entre QDs, à redução de energia do pico de PL com a diminuição de d. Observamos que o decaimento temporal de PL é independente de d e é relativamente rápido, ~0,6 ns, para uma estrutura com alinhamento de banda tipo-II. Isso sugere a presença de outros canais de captura de portadores de cargas reduzindo o tempo de vida dos éxcitons em nossos QDs. Observamos também uma redução do tempo de vida na região de maior energia de emissão em todas as amostras, indicando a transferência de portadores de cargas dos QDs muito pequenos para os grandes. O aumento da temperatura resultou na redução da energia de transição e da intensidade integrada nas medidas de PL-CW, bem como, do tempo de vida dos éxcitons. A redução da energia de transição se deve à transferência de elétrons dos QDs pequenos para grandes via wetting layer, devido à excitação térmica. Mas a contribuição desse efeito é menor nas amostras de QDs empilhados, devido aos efeitos de tunelamento dos elétrons entre QDs alinhados e à uniformidade dos tamanhos. A redução da intensidade integrada de PL e no tempo de decaimento se deve a excitação térmica do elétron para o estado contínuo da wetting layer
Abstract: We studied the optical and structural properties of stacked InP/GaAs quantum dots (QD) grown by the self-organized Stranskii-Krastanov mode in a chemical beam epitaxy system. The InP/GaAs quantum dots present type-II band alignment, where only the electron is confined in the QD, while the hole is localized around it, in the GaAs layer, due to the Coulomb attraction. We investigated samples with different space-layer d between two stacked InP QDs varying from 3 to 12 nm. The structural analysis was performed by using transmission electronic microscopy (TEM) and the optical analysis by using continuous wave (CW) and time-resolved (TR) photoluminescence (PL) techniques with temperature varying from 2 to 120 K. The TEM images show clear vertical alignment of quantum dots and slightly larger size for QDs of the second layer. The CW-PL spectra measured at low temperatures present narrower QD emission band and more symmetric for stacked QDs samples than single layer one. This is attributed to the uniformity of the QDs in double layers samples. We also observed the PL red-shift with the reduction of d, which is attributed to the quantum coupling and the tunneling effects of the carriers between aligned QDs. We observed that the PL decay time is independent of d and is relatively fast, ~0,6 ns, for a structure with type-II band alignment. This suggests the presence of other carrier capture channels that reduce significantly the exciton lifetime in our QDs. The carrier lifetime is shorter in the higher emission energy region in all samples, indicating the carrier transference from the smaller QDs to the larger ones. Increasing the temperature we observed a reduction of the transition energy and the integrated CW-PL intensity, as well as, of the exciton lifetime. The energy shift is due to the electron transference from the small QDs to the larger ones, through wetting layer, due to the thermal excitation. The contribution of this effect is smaller on the stacked QDs, due to the dot uniformity and the electron tunneling effect. The reduction of the CW-PL integrated intensity and the carrier decay time is due to the thermal excitation of the electron to the continuous state of the wetting layer
Mestrado
Física da Matéria Condensada
Mestre em Física
Ministro, José João Henrique. "A study on the synthesis and the optical properties of InP-based quantum dots." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/16836.
Full textThe aim of this work is the study of the optical properties of InP quantum dots (QDs) and the exploration of a new method for the synthesis of InP/CdS core-shell QDs. A multitude of research on colloidal QDs requires detailed knowledge of the relation between optical and structural properties, namely the sizing curve, the intrinsic absorption coefficient and the molar extinction coefficient. In this work, InP QDs were synthesized and structurally and optically characterized. The sizing curve was established from the average QD diameter, obtained by transmission electron microscopy, and the position of the first excitonic absorption peak. The intrinsic absorption coefficient and molar extinction coefficient were determined from quantitative elemental analysis and the absorbance of the nanocrystals at short wavelengths. We found that the intrinsic absorption coefficient is size-independent in this wavelength region and the molar extinction coefficient increases linearly with the QD volume. The focus of our study was then shifted to the fabrication of core-shell QD heterostructures, based on a recently reported method that used a more sustainable and much cheaper phosphorus precursor for the synthesis of high-quality InP/ZnS QDs. Using this procedure, we synthesized highly luminescent InP/CdS QDs and their emission could be tuned in the visible and near-infrared spectral regions. Furthermore, time-resolved photoluminescence measurements were performed on samples of InP/ZnS and InP/CdS QDs. We also report an exploratory study on the mechanism of formation of InP QDs with this new method. A thorough understanding of the reaction mechanism will enable a better control over the synthesis products and is potentially relevant for the fabrication of QDs consisting of other III-V semiconductors (e.g. GaP).
Li, Li. "Time-Resolved Optical Properties of Colloidal CdSe-CdS/ZnS Core-Multishell Quantum Dots in Bioimaging." Doctoral thesis, KTH, Cellens fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160939.
Full textQC 20150306
Yan, Yueran. "CdTe, CdTe/CdS Core/Shell, and CdTe/CdS/ZnS Core/Shell/Shell Quantum Dots Study." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1327614907.
Full textDonat, Florian. "Microréacteurs photocatalytiques utilisant des oxydes métalliques semi-conducteurs sensibilisés par des Quantum Dots CuInS2/ZnS." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0085/document.
Full textThe pollution of hospital effluents by pharmaceutical drugs, requires the development of new treatment techniques. Among these processes, photocatalysis is one of the most efficient one and allows the remediation of this kind of pollution. However, metal oxides used for photocatalysis (TiO2, ZnO, …) can only be activated by UV light. The association of these oxides with quantum dots (QDs) creates an heterojunction, which not only allows to extend the activation spectrum of the photocatalyst to the visible region but also decreases the charge carriers recombinations. The first part of this work describes the development of a catalyst responding to solar light irradiation for the degradation of the Orange II dye. First, we characterized the heterojunction created between ZnO and the CuInS2/ZnS (ZCIS) QDs and evaluated their photocatalytic efficiency. This work was undertaken by evaluating the capacity of the ZnO/ZCIS catalyst to produce reactive oxygen species (ROS). In the second part, we studied the photodegradation of the antineoplastic agent Ifosfamide commonly found in hospital effluents. For this purpose, closed and agitated reactors but also microreactors were used. In both cases, Ifosfamide, and the compounds originating from its degradation, can be fully photodegraded under simulated light of weak intensity (5 mW/cm2) using the ZnO/ZCIS catalyst. In the case of microreactors, the deposition of the catalyst was optimized and its stability evaluated. Results obtained demonstrate that the ZnO/ZCIS catalyst can be reused, at least five times, without significant loss in activity, thus demonstrating its ability to be used in real photocatalytic applications
Bommer, Moritz [Verfasser]. "InP/(Al,Ga)InP Quantum Dots on GaAs- and Si-Substrates for Single-Photon Generation at Elevated Temperatures / Moritz Bommer." München : Verlag Dr. Hut, 2013. http://d-nb.info/1042308225/34.
Full textKeßler, Christian [Verfasser]. "Electrically Driven Single-Photon Sources Based on InP/GaInP Quantum Dots: Characterization and Application in Quantum Communication / Christian Keßler." München : Verlag Dr. Hut, 2015. http://d-nb.info/1077403941/34.
Full textKeßler, Christian Alexander [Verfasser]. "Electrically Driven Single-Photon Sources Based on InP/GaInP Quantum Dots: Characterization and Application in Quantum Communication / Christian Keßler." München : Verlag Dr. Hut, 2015. http://d-nb.info/1077403941/34.
Full textAdegoke, Oluwasesan, Tebello Nyokong, and Patricia B. C. Forbes. "Structural and optical properties of alloyed quaternary CdSeTeS core and CdSeTeS/ZnS core–shell quantum dots." Elsevier, 2015. http://hdl.handle.net/10962/d1020248.
Full textOriginal publication is available at http://dx.doi.org/10.1016/j.jallcom.2015.05.083
Shen, Yaoming. "Photoluminescence spectral study of single CdSe/ZnS Colloidal Nanocrystals in Poly(methyl methacrylate) and Quantum Dots molecules." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3304209.
Full textTitle from first page of PDF file (viewed June 17, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 91-99).
Bouwer, James Christopher. "Preparation, theory, and biological applications of highly luminescent CdSe/ZnS quantum dots in optical and electron microscopy /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3061628.
Full textBommer, Moritz [Verfasser], and Peter [Akademischer Betreuer] Michler. "InP-(Al,Ga)InP quantum dots on GaAs- and Si-substrates for single-photon generation at elevated temperatures / Moritz Bommer. Betreuer: Peter Michler." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2013. http://d-nb.info/1038695120/34.
Full textChauviré, Timothée. "Développement de systèmes photochimiques à base de Quantum Dots hydrosolubles de type coeur CdSe et coeur-coquille CdSe/ZnS." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENV039/document.
Full textThe use of colloidal semiconductor nanoparticles, called quantum dots, is recent in redox photocatalysis. Those nanostructures exhibit strong and size depending visible absorption properties. The ligand shell on the nanoparticle surface can be furthermore managed to realize green applications. Thus the study of redox photocatalysis with core CdSe nanoparticles and core-shell CdSe/ZnS was carried out with visible light in aqueous solvent. Firstly, we synthetized hydrophilic quantum-dots stabilized by amino acids ligands. Secondly, we perform three different studies of photocatalytic systems with the following substrates : modified amino acids, vanillin and 8oxodG. The nanoparticle's photochemical activity was first demonstrated and evaluated by the detection of photochemical products. The photoinduced charge transfer mechanism was elucidated during irradiation by spectroscopic techniques
Kristukat, Christian. "High pressure study of the electronic structure of self-assembled InAs/GaAs and InP/GaP quantum dots." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=97877339X.
Full textRaevskaya, Alexandra, Vladimir Lesnyak, Danny Haubold, Volodymyr Dzhagan, Oleksandr Stroyuk, Nikolai Gaponik, Dietrich R. T. Zahn, and Alexander Eychmüller. "A Fine Size Selection of Brightly Luminescent Water-Soluble Ag-In-S and Ag-In-S/ZnS Quantum Dots." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-226647.
Full textKrasselt, Cornelius, Jörg Schuster, and Borczyskowski Christian von. "Photoinduced hole trapping in single semiconductor quantum dots at specific sites at silicon oxide interfaces." Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-122745.
Full textJunior, João Batista Souza. "Síntese de nanoestruturas core/shell de Co/Au magnetoplasmônica e pontos quânticos de CdSe/ZnS." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-28072017-170738/.
Full textNanomaterials properties are size- and shape-controlled, such as the superparamagnetism phenomenon of magnetic nanoparticles or the quantum confinement of charge carriers of quantum dots. Therefore, synthesis of monodisperse spherical nanoparticles became extremely important over the past few deacades, since nanoparticles can be used for plenty of applications in technology and biomedicine. Magnetic nanoparticles and quantum dots are promising materials for diagnosis and therapy of cancer. Spherical nanoparticles of metallic cobalt were synthesized with mean diameter of 5,3 nm and standard deviation of 0,4 nm, lognormal distribution. A modified Langevin equation using the interacting superparamagnetic model was used to fit magnetization curves obtaining the mean magnetic diameter and standard deviation, 4,7 nm and 1,0 nm, respectively. The difference between these two diameters was assigned to the magnetic dead layer (∼3.0 Å), which does not contribute to the sample magnetization, being the saturation magnetization of cobalt nanoparticles around 125 emu g-1. Co/Au core/shell nanostructures were synthesized and the surface plasmon ressonance property was observed, an additional property also desired for biomedical applications, being the Co/Au core/shell system called magnetoplasmonic. CdSe quantum dots were synthesized with high size- and shape-controlled. Using different synthetic routes from the classic TOP-TOPO synthesis, and selenium dioxide as a precursor, the results show that and reducing agent is necessary and 1-octadecene solvent leads to better optical properties. CdSe samples showed a zinc blend (cubic phase) crystal structure, different from TOP-TOPO syntheses that leads to wurtzite structure (hexagonal phase). The growth kinetics of CdSe particles were also evaluated through aliquots from reaction showing exponential growth of particles diameter, as predicted on the theory of nucleation and growth. Fluorescence microscopy studies showed that quantum dots exhibited fluorescence intermittence behavior already reported in the literature as one fo the reasons for the quantum yield decrease. CdSe/ZnS core/shell nanostructures were obtained with high control of the coating layer thickness and the increase of the photoluminescence properties were shown.
Oluwole, David O., Jonathan Britton, Philani Mashazi, and Tebello Nyokong. "Synthesis and photophysical properties of nanocomposites of aluminum tetrasulfonated phthalocyanine covalently linked to glutathione capped CdTe/CdS/ZnS quantum dots." Elsevier, 2015. http://hdl.handle.net/10962/d1020291.
Full textOriginal publication is available at http://dx.doi.org/10.1016/j.synthmet.2015.04.015
Adegoke, Oluwasesan, Tebello Nyokong, and Patricia B. C. Forbes. "Deposition of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shells around CdSeTe alloyed core quantum dots: effects on optical properties." Wiley, 2015. http://hdl.handle.net/10962/d1020342.
Full textOriginal publication is available at http://dx.doi.org/10.1002/bio.3013
Bump, Buddy J. "Synthesis and Characterization of CdSe/ZnS Core/Shell Quantum Dot Sensitized PCPDTBT-P3HT:PCBM Organic Photovoltaics." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1309.
Full textSalverson, 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 textBufon, Carlos César Bof\'. "Propriedades eletrônicas de pontos quânticos de InAs1-xPx sobre GaAs." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-09032009-152432/.
Full textThe growth of quantum dots in the Stranski-Krastranov mode has been subject of intense investigation in the last decade. Knowing the electronics properties of these materials is key for performing quantum systems engineering. The objective of this work is to study the quantum dots (QD) electronic properties of the InAS1-x Px embedded in GaAs. The study was done by capacitance spectroscopy (CV), which is an experimental tool that allows the evaluation of the electronic states and the charge distribution of a given quantum device. The samples of InAS1-x Px were grown by Low-Pressure Metalorganic Chemical Vapor Deposition on GaAs:Cr (001) substrates. They consist of metalinsulator-semiconductor structures with an n-type back contact. The measurements were performed at 4.2 K for different values of frequencies and magnetic field. From the confined states dispersion as a function of the applied magnetic field, perpendicular to the QD plane, the system natural frequency, ◚, was determined. From the ◚, we could determine the wave function characteristic length, . The concordance between the , values and the lateral sizes obtained by Transmission Electronic Microscopy (TEM) is good. Finally, by CV spectroscopy we could separate the lateral and vertical confinement effects, leading to a more complete understanding of the Photoluminescence (PL) spectra, as well as the details of the QD shape obtained by TEM.
Akanuma, Y., I. Yamakawa, Y. Sakuma, T. Usuki, and A. Nakamura. "Sharp Interfacial Structure of InAs/InP Quantum Dots Grown by a Double-Cap Method: A Cross-Sectional Scanning Tunneling Microscopy Study." American Institite of Physics, 2007. http://hdl.handle.net/2237/12037.
Full textClift, Martin James David. "Quantum dots : an investigation into how differing surface characteristics affect their interaction with macrophages in vitro." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/2557.
Full textMONTEIRO, Thatyara Oliveira. "Sensores fotoeletroquímicos explorando o tetracianoetileneto de lítio (LiTCNE) na determinação do antioxidante terc-butil hidroquinona (TBHQ)." Universidade Federal do Maranhão, 2017. https://tedebc.ufma.br/jspui/handle/tede/tede/1949.
Full textMade available in DSpace on 2017-10-02T19:59:47Z (GMT). No. of bitstreams: 1 ThatyaraMonteiro.pdf: 3528798 bytes, checksum: 12d3da9115c45896b4f14c67dbe3d20e (MD5) Previous issue date: 2017-09-01
Two novel and pioneering photoelectrochemical sensors were developed for determination of tert-butyl hydroquinone (TBHQ) in biodiesel and edible oil samples. The former based on composite formed by TiO2 nanoparticles and lithium tetracyanethylene (LiTCNE), and the last based on the sensitization of CdSe/ZnS quantum dots with LiTCNE. In both cases, indium tin oxide (ITO) was used as the work electrode surface. The LiTCNE/TiO2/ITO sensor showed a TBHQ photocurrent about 28-fold higher than the TiO2 sensor. The same was observed for the CdSe/ZnS/LiTCNE/ITO sensor, which presented a photocurrent for TBHQ about 13-fold higher than that presented by the electrode modified with CdSe/ZnS. Both developed sensors showed lower resistance to charge transfer than their non-sensitized components. They also demonstrated high selectivity to TBHQ, with high photocurrent for this compound in comparison to photocurrent responses to other phenolic antioxidants. The experimental conditions optimized for both sensors were: 0.1 mol L-1 of phosphate buffer solution pH 7.0 and applied potential to the working electrode of 450 mV, for the LiTCNE/TiO2/ITO sensor, and 0.1 mol L-1 of phosphate buffer solution pH 6.0, and potential of 400 mV for the CdSe/ZnS/LiTCNE/ITO sensor. In these conditions, the sensors presented a linear range of TBHQ response between 0.4 and 500 μmol L-1 for LiTCNE/TiO2/ITO sensor and between 0.6 and 250 μmol L-1 for the CdSe/ZnS/LiTCNE/ITO sensor, with limits of detection of 0.10 and 0.21 μmol L-1, respectively. The LiTCNE/TiO2/ITO sensor was applied in biodiesel samples for determination of TBHQ using standard addition method, showing recovery values between 96.8 and 98.2%. The CdSe/ZnS/LiTCNE/ITO sensor was applied in edible oil samples to detect TBHQ using an external calibration method, with recovery values between 98.25 and 99.83%. The photoelectrochemical sensors were successfully used to determine the TBHQ antioxidant in real samples of biodiesel and vegetable oil.
Dois novos e pioneiros sensores fotoeletroquímicos foram desenvolvidos para determinação de tert-butil hidroquinona (TBHQ) em amostras de biodiesel e de óleo comestível. O primeiro baseado no compósito formado por nanopartículas de TiO2 e tetracianoetileneto de lítio (LiTCNE), e o segundo baseado na sensibilização de quantum dots CdSe/ZnS com o LiTCNE. Em ambos os casos utilizou-se como eletrodo de trabalho o óxido de índio e estanho (ITO) como superfície eletródica. O sensor à base de LiTCNE/TiO2/ITO apresentou uma fotocorrente para o TBHQ cerca de 28 vezes mais elevada que o sensor à base de TiO2. O mesmo foi observado para o sensor à base de CdSe/ZnS/LiTCNE/ITO, que apresentou fotocorrente para o TBHQ cerca de 13 vezes maior do que à apresentada pelo eletrodo modificado com CdSe/ZnS. Ambos os sensores desenvolvidos apresentaram baixa resistência à transferência de carga em comparação a seus componentes não sensibilizados. Também demonstraram grande seletividade ao TBHQ, com alta fotocorrente para esse composto em comparação às respostas de fotocorrente para outros antioxidantes fenólicos. As condições experimentais otimizadas para ambos os sensores desenvolvidos foram, respectivamente: 0,1 mol L-1 de solução tampão fosfato pH 7,0 e potencial aplicado ao eletrodo de trabalho de 450 mV, para o sensor LiTCNE/TiO2/ITO, e 0,1 mol L-1 de solução tampão fosfato pH 6,0, e potencial de 400 mV, para o sensor CdSe/ZnS/LiTCNE/ITO. Nessas condições, os sensores apresentaram faixa linear de resposta de TBHQ entre 0,4 a 500 µmol L-1 para sensor LiTCNE/TiO2/ITO e entre 0,6 a 250 µmol L-1 para o sensor CdSe/ZnS/LiTCNE/ITO, apresentando limites de detecção de 0,10 e 0,21 µmol L-1 , respectivamente. O sensor LiTCNE/TiO2/ITO foi aplicado em amostras de biodiesel para determinação de TBHQ usando método de adição de padrão, mostrando valores de recuperação entre 96,8 e 98,2%. Já o sensor CdSe/ZnS/LiTCNE/ITO foi aplicado em amostras de óleo comestível para detecção de TBHQ usando método de calibração externa, com valores de recuperação entre 98,25 e 99,83%. Os sensores fotoeletroquímicos foram empregados com sucesso para determinação de antioxidante TBHQ em amostras reais de biodiesel e óleo vegetal.
Bouchonville, Nicolas. "Nouveau nano-matériau hybride – nanocristaux de CdSe/ZnS couplés à la bactériorhodopsine – pour des applications en optoélectronique et en biologie : élaboration et caractérisations structurale et optique." Thesis, Reims, 2011. http://www.theses.fr/2011REIMS017/document.
Full textIn this work, we built and characterized a new hybrid material with energy transfer properties made from photochromic protein Bacteriorhodopsin (bR) which is the energy acceptor and CdSe/ZnS fluorescent quantum dots (QDs) which are the energy donor. Our aim was to improve the photochromic and photo-physical bR properties by using a Förster resonance energy transfer (FRET) which should exist in presence of semiconductor QDs. This new hybrid material should have applications in many fields such as optical switching or photovoltaics.Since optical properties and efficiency of such a material are highly dependent of its structure, our work was to develop and characterize bR/QD complex by atomic force microscopy (AFM) and optical spectrometries (fluorescence, absorption) in order to demonstrate FRET between bR and QDs. By tuning QDs surface charges, we proved that we were able to optimize FRET, by optimization of the electrostatic interactions between bR and QDs. This effect was due to a better organization of QDs on the membrane surface when interactions were optimized. We also showed that when QD and bR are linked by biotin streptavidin link they revealed the maximum FRET efficiency of 80 %.During all these experiments, we showed that QDs could induce a quicker detergent monomerization of bR. This is supported by AFM images and circular dichroïsm measurements. This effect should find applications in biology
Godoy, Marcio Peron Franco de. "Propriedades de pontos quânticos de InP/GaAs." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277715.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-06T18:02:06Z (GMT). No. of bitstreams: 1 Godoy_MarcioPeronFrancode_D.pdf: 4057709 bytes, checksum: 0df1e56082150d4109dcf891f05d4da6 (MD5) Previous issue date: 2006
Resumo: Neste trabalho estudamos as propriedade estruturais e ópticas de pontos quânticos auto-organizados de InP crescidos sobre o substrato de GaAs. Esta estrutura apresenta o alinhamento de bandas tipo-II na interface, confinando o elétron no ponto quântico, enquanto o buraco mantém-se na barreira, próximo à interface devido à interação coulombiana atrativa. As amostras foram crescidas por epitaxia de feixe químico (CBE) no modo Stranskii-Krastanov. Os pontos quânticos apresentam raio médio de 25 nm e grande dispersão de altura (1-5 nm) e ocorre a relaxação parcial do parâmetro de rede, chegando a 2 %, em pontos quânticos superficiais. Do ponto de vista de propriedades ópticas, a fotoluminescência de pontos quânticos superficiais exibe uma eficiente emissão óptica, devido a baixa velocidade de recombinação dos estados superficiais do InP, e reflete a densidade e distribuição bimodal de tamanhos. Além disso, sua emissão óptica em função da intensidade de excitação exibe comportamento diverso em comparação com pontos quânticos cobertos com uma camada de GaAs. Em pontos quânticos cobertos, determinamos a energia de ativação térmica, que varia de 6 a 8 meV, e é associada à energia de ligação do éxciton ou energia de ionização do buraco. O decaimento temporal da luminescência de pontos quânticos é de 1,2 ns, um tempo relativamente curto para um ponto quântico tipo-II. A análise das propriedades magneto-ópticas em pontos quânticos individuais, inédita em QDs tipo-II, permitiu verificar que o fator-g do éxciton é praticamente constante, independentemente do tamanho dos QDs, devido ao fato dos buracos estarem levemente ligados. Por fim, mostramos a versatilidade do sistema acoplando-o a um poço quântico de InGaAs. Este acoplamento introduz mudanças na superposição das funções de onda do par elétron-buraco que permitem a manipulação do tempo de decaimento da luminescência e da energia de ligação excitônica
Abstract: We have investigated structural and optical properties of InP self-assembled quantum dots grown on GaAs substrate. This system presents a type-II band lineup where only electrons are confined in the InP quantum dots. The InP/GaAs quantum dots were grown by chemical beam epitaxy in the Stranskii-Krastanov mode. Our quantum dots present a mean radius of 25 nm and large height dispersion, 1-5 nm, and a partial relieve of the strain up to 2 % is observed. The photoluminescence spectra of surface quantum dots show an efficient optical emission, which is attributed to the low surface recombination velocity in InP. We observed a bimodal dispersion of the dots size distribution, giving rise to two distinct emission bands. A remarkable result is the relatively large blue shift of the emission band from uncapped samples as compared to those for capped dots. In capped quantum dots, we obtained the thermal activation energy, from 6 to 8 meV, which is associated to the exciton binding energy or hole ionization energy. The observed luminescence decay time is about 1.2 ns, relatively short decay time for type II system. We investigated magneto-optical properties using single-dot spectroscopy. The values of the exciton g factor obtained for a large number of single InP/GaAs dots are mainly constant independent of the emission energy and, therefore, of the quantum dot size. The result is attributed to the weak confinement of the holes in InP/GaAs QDs. We have also investigated structures where InP quantum dots are coupled to a InGaAs quantum well. This system permits the manipulation of the wave function overlap between electron-hole in order to control the optical emission decay time and exciton binding energy
Doutorado
Física
Doutor em Ciências
Ugur, Katmis Asli [Verfasser], W. Ted [Akademischer Betreuer] Masselink, Mete [Akademischer Betreuer] Atat¨ure, and Henning [Akademischer Betreuer] Riechert. "Growth and characterization of InP/In0.48Ga0.52P quantum dots optimized for single-photon emission / Asli Ugur Katmis. Gutachter: W. Ted Masselink ; Mete Atat¨ure ; Henning Riechert." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://d-nb.info/1032944218/34.
Full textGrimes, Logan. "DEVELOPENT OF A PHOSPHOLIPID ENCAPSULATION PROCESS FOR QUANTUM DOTS TO BE USED IN BIOLOGIC APPLICATIONS." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1237.
Full textDupuy, Emmanuel. "Croissance et spectroscopie de boîtes quantiques diluées d'InAs/InP(001) pour des applications nanophotoniques à 1,55 µm." Phd thesis, Ecole Centrale de Lyon, 2009. http://tel.archives-ouvertes.fr/tel-00616499.
Full textFelle, Martin Connor Patrick. "Telecom wavelength quantum devices." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/270019.
Full textTzeng, Jia-Yu, and 曾嘉羽. "Device characterization of InP/ZnS colloidal dots on InGaAs Quantum Dots Solar cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/x4zr65.
Full text國立中興大學
光電工程研究所
107
We use colloidal InP/ZnS quantum dots coating on InGaAs QD solar cells. The power conversion efficiency of the solar cell is improved by the light absorption of the upper InP/ZnS colloidal quantum dots and the secondary light absorption of the InGaAs quantum dots in the solar cells. The EQE measurement of the solar cells without InP/ZnS quantum dots shows a conversion peak at about 700 nm. In order to increase the light absorption of the solar cells, we use 750 nm quantum dots coating on the solar cells, and grow gold nanoparticles above the solar cells to increase the uniformity of colloidal quantum dots dispersion. First, the samples were deposited by atomic deposition (Atomic Layer Deposition, ALD) with 50 nm HfO2 and 50 nm Al2O3 as the heat collecting layer, then use a thermal evaporation to coat a thin layer of Au and use different annealing time to form gold nanoparticles. And then we take a picture of SEM to confirm the formation of the gold nanoparticles. The effect of gold nanoparticles forming is most significant when the annealing temperature is 450℃ and the annealing time is 90 seconds. Finally, samples proceed to the high-concentration I-V measurement and external quantum efficiency (EQE) measurement. The power conversion efficiency of C536 is enhanced from 8.2% to 9.8% by coating the gold nanoparticles and 15% InP/ZnS colloidal quantum dots.
Chen, To-Yuan, and 陳鐸元. "Bio-oriented interface of InP/ZnS quantum dots through octenyl succinic anhydride modification." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/76793a.
Full text中原大學
生物醫學工程研究所
102
Recently, the unique optical properties of quantum dot gradually replace the traditional organic fluorescent dyes and fluorescent proteins in the field of biomedical technology. It has become important tools in related biomedical areas, such as cell targeting, cell tracking. But the material for the synthesis of traditional quantum dot contains heavy metal, such as Cd2+、Pb2+, which will cause serious toxicity for both biological and environmental pollution. Scientists have investigated the alternative materials to replace heavy metal ions and thereby increase its potential in biomedical applications. This study focused on engineering hydrophobic InP/ZnS quantum dots and on the use of octenyl succinic anhydride (OSA) toward bioconjugation. Using a simple, fast microemulsion method not only can modify the hydrophobic InP/ZnS Quantum dots to be hydrophilic ones but also transfer versatile hydrophobic nanoparticles to aqueous phase successfully. However, the buffer layer structure conposed by the octenyl succinic anhydride was unsteady, it was prone to result in disintegration in diluted condition. Then we further showed that using polyethylene glycol monomethyl ether as the surface modifier can increase the stability of InP/ZnS hydrophilic structure. Subsequently, using DSPE-PEG-X (X: -amine, -carboxyl, -methoxy) can further functionalized the surface which can be verified by gel electrophoresis. In this study, we found that the use of octenyl succinic anhydride can offer superior hydrophilic modification of InP/ZnS quantum dots and that the use of polyethylene glycol monomethyl ether can increase stability of buffer layer to improve the stability after phase transfer. We envision the coating method will expand the nanomaterials applying in biomecial research.
Hung, Shih-Ting, and 洪詩婷. "Fabrication of High Luminous Efficacy InP/ZnS Core-Shell Quantum dots for Application to Light-Emitting Diodes." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/98448177402680271758.
Full text國立臺灣師範大學
化學系
104
Semiconductor quantum dots (QDs), of which particle sizes are in the nanometer scale, have very unusual size-controllable optical properties. However, the well-developed Cadmium-based QDs are restricted in further application due to its acute toxicity, making it necessary to find the alternative materials. Among all the possible alternatives, indium phosphide(InP) shows promising in both optical and electric properties, which can be later introduced into application. The environment-friendly InP quantum dots (QDs) have been synthesized in this paper by the conventional hot injection method using a non-toxic precursor of P(TMS)3. To enhance the material durability, the InP would be covered by ZnS, forming the InP/ZnS core-shell structure. The carefully controlled syntheses of a series of InP/ZnS QDs were designed by varying the core-growth temperature and the concentrations of precursor. The environment-friendly InP/ZnS is set to have further application in electronic devices. Therefore, heat resistance and surface smoothness were also examined in our work. In the test of heat resistant, InP/ZnS quantum dots were annealed under different temperature and time, which shows possible to the light-emitting diodes (LEDs) converters. Over all, using fatty-acid as the surfactant, the InP/ZnS QDs have revealed the potential for the fabrication of solid-state lighting.