Готові списки джерел за темами / Nanocrystals - Luminescence

Добірка наукової літератури з теми "Nanocrystals - Luminescence"

Автор: Grafiati
Опубліковано: 7 вересня 2023

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Статті в журналах з теми "Nanocrystals - Luminescence"

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Mukhina, Maria V., Vladimir G. Maslov, Ivan V. Korsakov, Finn Purcell Milton, Alexander Loudon, Alexander V. Baranov, Anatoly V. Fedorov, and Yurii K. Gun’ko. "Optically active II-VI semiconductor nanocrystals via chiral phase transfer." MRS Proceedings 1793 (2015): 27–33. http://dx.doi.org/10.1557/opl.2015.652.

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ABSTRACTWe report optically active ensembles of II-VI semiconductor nanocrystals prepared via chiral phase transfer, which is initiated by exchange of the original achiral ligands capping the nanocrystals surfaces for chiral L- and D-cysteine. We used this method to obtain ensembles of CdSe, CdS, ZnS:Mn, and CdSe/ZnS quantum dots and CdSe/CdS quantum rods exhibited Circular Dichroism (CD) and Circularly Polarized Luminescence (CPL) signals. The optically active nanocrystals revealed the CD and CPL bands strongly correlated with absorption and luminescence bands with unique band “pattern” for each material and the nanocrystal shape.
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Korbutyak, D. V. "SURFACE LUMINESCENCE OF A2B6 SEMICONDUCTOR QUANTUM DOTS (REVIEW)." Optoelektronìka ta napìvprovìdnikova tehnìka 56 (December 7, 2021): 27–38. http://dx.doi.org/10.15407/iopt.2021.56.027.

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Semiconductor zero-dimensional nanocrystals – quantum dots (QDs) – have been increasingly used in various fields of opto- and nanoelectronics in recent decades. This is because of the exciton nature of their luminescence, which can be controlled via the well known quantum-dimensional effect. At the same time, at small nanocrystall sizes, the influence of the surface on the optical and structural properties of nanocrystals increases significantly. The presence of broken bonds of surface atoms and point defects – vacancies and interstial atoms – can both weaken the exciton luminescence and create new effective channels of radiant luminescence. In some cases, these surface luminescence becomes dominant, leading to optical spectra broadening up to the quasi-white light. The nature of such localized states often remains unestablished due to the large number of the possible sorts of defects in both of QD and its surrounding. In contrast to exciton luminescence, which can be properly described within effective-mass approximations, the optical properties of defects relay on chemical nature of both defect itsself and its surrounding, what cannot be provided by “hydrogen-type coulomb defect” approximation. Moreover, charge state and related to this lattice relaxation must be taken into account, what requires an application of atomistic approach, such as Density functioal theory (DFT). Therefore, this review is devoted to the study of surface (defect) states and related luminescence, as well as the analysis of possible defects in nanocrystals of semiconductor compounds A2B6 (CdS, CdZnS, ZnS), responsible for luminescence processes, within ab initio approach. The review presents the results of the authors' and literature sources devoted to the study of the luminescent characteristics of ultra-small (<2 nm) QDs.
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Cui, Fang, Tong Jie Yao, Jing Yu, and Ke Ning Sun. "Synthesis and Characterization of Luminescent TiO2/Polymer Nanocomposites." Advanced Materials Research 873 (December 2013): 492–95. http://dx.doi.org/10.4028/www.scientific.net/amr.873.492.

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Анотація:
Transparent luminescent TiO2/polymer nanocomposites were obtained through the combined use of copolymerization of a novel titanium ion containing monomer with a liquidsolid reaction. The titanium ions are covalently introduced into polymer chains and transformed into TiO2 nanocrystals directly in the solid-state polymer matrices. That allows the generation of high-quality anatase TiO2 nanocrystals with a narrow size distribution in the polymer matrices. The luminescence of the TiO2 nanocrystals is dominated by band-edge luminescence at room temperature.
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Valiev, Damir, Rufina Kharisova, Anastasiia Babkina, Ksenia Zyryanova, Natalia Kuzmenko, Yevgeniy Sgibnev, Artem Shelaev, and Alexander V. Baryshev. "Highly Luminescent Rb-Doped Cs4PbBr6 Nanocrystals in Borogermanate Glass." Photonics 10, no. 7 (June 26, 2023): 729. http://dx.doi.org/10.3390/photonics10070729.

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Анотація:
For the first time, the synthesis, luminescent and structural properties of stable perovskite-type (Cs1−xRbx)4PbBr6 (R = Cs, Rb) nanocrystals are shown. In the absence of rubidium, Cs4PbBr6 and CsPbBr3 perovskite crystals precipitate in the ZnO–Na2O–B2O3–GeO2 glass matrix. With ascending rubidium content, the precipitation of (Cs,Rb)4PbBr6 nanocrystals is replaced by the Rb4PbBr6 nanocrystals nucleation. Nucleated nanocrystals exhibit an intense green luminescence. With an increase of the rubidium content, the luminescence maximum shifts to the blue region, the luminescence quantum yield increases from 28 to 51%, and the average decay time increases from 2 to 8 ns. Several assumptions have been made about the nature of the green luminescence of perovskite-like Cs4PbBr6 and (Cs,Rb)4PbBr6 crystals in glasses. It is concluded that the most probable cause is the impurity inclusions of CsPbBr3 and (Cs,Rb)PbBr3 crystals.
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Shvalagin, Vitaliy, Galyna Grodziuk, Olha Sarapulova, Misha Kurmach, Vasyl Granchak, and Valentyn Sherstiuk. "Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles." Journal of Nanotechnology 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/2708638.

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For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.
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Wang, Shanshan, Zhangkun Liu, Yuxiu Zou, Xiaofang Lai, Ding Ding, Long Chen, Liqin Zhang, Yuan Wu, Zhuo Chen, and Weihong Tan. "Elucidating the cellular uptake mechanism of aptamer-functionalized graphene-isolated-Au-nanocrystals with dual-modal imaging." Analyst 141, no. 11 (2016): 3337–42. http://dx.doi.org/10.1039/c6an00483k.

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Bendre, B. S., and Shailaja Mahamuni. "Luminescence in ZnO Quantum Particles." Journal of Materials Research 19, no. 3 (March 2004): 737–40. http://dx.doi.org/10.1557/jmr.2004.19.3.737.

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Анотація:
Wet-chemical and electrochemical routes were used to synthesize zinc oxide nanoparticles showing peculiar luminescent properties. ZnO-I are the nanoparticles that show only band gap ultraviolet (UV) emission, whereas ZnO-II type nanoparticles show the defect green luminescence along with the UV emission. Photoluminescence excitation (PLE) spectra of ZnO-I nanocrystals exhibit a single feature located at about 368 nm whereas ZnO-II nanocrystals show two features in PLE: a prominent feature at about 368 nm which is size dependent and a hump at 325 nm. These results are discussed in detail in view of the luminescence behavior in ZnO quantum particles.
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Pan, Er, Gongxun Bai, Yutao Peng, Liang Chen, and Shiqing Xu. "Promoting luminescence of Yb/Er codoped ferroelectric composite by polarization engineering for optoelectronic applications." Nanophotonics 8, no. 12 (September 17, 2019): 2215–23. http://dx.doi.org/10.1515/nanoph-2019-0230.

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AbstractFerroelectric oxide nanocrystals, in combination with the robust coupling of an electric field with crystal structure symmetry, makes such systems agreeable to field-induced crystal structural transformation. The luminescent properties of rare earth ions are sensitive to the symmetry of the surrounding crystal field. The luminescence tuning of rare earth ions is an important assignment in the research of luminescent materials. However, the current conditional feasibility and reversibility in the exploration of luminescence modification remain major challenges. In this article, the luminescence modulation of rare earth ions has been developed in Yb3+/Er3+ codoped ferroelectrics glass ceramics containing Bi4Ti3O12 nanocrystals through an electric field. The inclusion of nanocrystals in the glass matrix greatly enhances the electrical resistance. Both upconversion and near-infrared emissions of rare earth ions are effectively enhanced more than twice via polarization engineering. The electric field regulates the photonic properties of rare earth ions with excellent reversibility and nonvolatility in ferroelectrics. The effective modification by electric field provides a new scheme for optical storage and optoelectronic devices.
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LI, JUN, KUI ZHAO, RUOKUN JIA, YANMEI LIU, YUBAI BAI, and TIEJIN LI. "USING EMISSION QUENCHING TO STUDY THE INTERACTION BETWEEN ZnO NANOCRYSTALS AND ORGANIC LIGANDS." International Journal of Nanoscience 01, no. 05n06 (October 2002): 743–47. http://dx.doi.org/10.1142/s0219581x02000991.

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Анотація:
Colloidal ZnO nanocrystals with strong green luminescence were prepared. When ZnO nanocrystals were modified with different organic ligands, the emission quenching was measured and used to study the interaction between ZnO nanocrystal and organic ligands. Efficiency of emission quenching relates to the chemical structures of the ligands, and metal-thiolate bond was formed between nanocrystals and thiol ligands. The relative strength of the binding and the surface concentration of the adsorbed species could be determined using this method.
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Kataoka, Takuya, Shigeaki Abe, and Motohiro Tagaya. "Synthesis of Europium(III) Complex-Based Hydroxyapatite Nanocrystals for Biolabeling Applications." Key Engineering Materials 782 (October 2018): 41–46. http://dx.doi.org/10.4028/www.scientific.net/kem.782.41.

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We synthesized the inorganic/organic hybrid nanocrystal (EHA) by hydroxyapatite (HA) nanocrystal growth under the existence of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)europium(III) (EuTH) complex. Then, folic acid derivative (FA-NHS: folate N-hydroxysuccinimidyl ester) as the targeting ligand for the HeLa cancer cells was immobilized on the EHA by the mediation of 3-aminopropyltriethoxysilane (APTES) and methyltriethoxysilane (MTES). When the FA-NHS molecular occupancy ratio on the EHA surface is around 3 to 5 %, the strong luminescence from the f-f transition of the Eu3+ ion and luminescence associated with energy transfer between the EuTH-FA monomer near 518 nm were observed. Moreover, the dispersibility in phosphate buffer saline was confirmed with immobilizing the positively-charged FA-NHS. The affinity and non-cytotoxicity between the nanocrystals and HeLa cancer cells were confirmed for 3 days. The red luminescence from the cells could be observed by fluorescence microscopy and the luminescence spectra.
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Більше джерел

Дисертації з теми "Nanocrystals - Luminescence"

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Maksimchuk, P., A. Masalov, V. Seminko, and Yu Malyukin. "Formation of Luminescence Centers in Oxygen-Deficient Cerium Oxide Nanocrystals." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35446.

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In this work the peculiarities of oxygen vacancies formation in cerium oxide nanoparticles for different external influences have been investigated by spectroscopic methods. The features of oxygen vacancies and therefore non-stoichiometric cerium oxide formation in CeO2 nanocrystals depending on the atmosphere of high temperature treatment were investigated. Stimulation of oxygen vacancies formation in reducing and neutral atmospheres was revealed. Occurrence of two different luminescence centers (viz. the charge-transfer complexes formed by Ce4+ and O2- ions, and Ce3+ ions stabilized by vacancies) after cerium oxide nanoparticles annealing in a neutral atmosphere has been observed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35446
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2

SARTORI, EMANUELA. "EMISSIVE NANOCRYSTALS FOR OPTOELECTRONIC APPLICATIONS." Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1074636.

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Анотація:
Metal halide perovskites (particularly doped perovskites and lead free double perovskites) are starting to generate great interest in the scientific community due to their unique electronic and structural properties, such as high photoluminescent quantum yields (PLQY, up to 90%), chemical diversity in terms of elements employed and tunable optical properties. Consequently, their application in optoelectronic devices gained attention. During these three years, I intensively worked on the synthesis and characterization of inorganic perovskites nanocrystals, starting from lead halide perovskites (LHPs) in 3D and 0D structure and then moving to the double perovskites (DPs). Generally, the aim of these studies is to replace Pb with less toxic elements, producing materials more stable to atmosphere conditions and with good optical properties. Thus, synthesis and optimization are the key words of this part of the work. Pb has been replaced with a monovalent (Ag, Na) and a trivalent (In, Bi), or a bivalent (Cu, Mn) and a trivalent (Sb) metal cation, leading to DPs (e.g. Cs2AgInCl6) and layered perovskites (e.g. Cs4CuSb2Cl12), respectively. However, perovskites are not the only promising candidate for optoelectronic devices, in particular considering the increasing interest in studying NIR emitting materials. In this field, my work on silicates takes place. In fact, Cu - based silicates (e.g. CaCuSi4O10) possess a high emission in NIR region (900–1000 nm). Moreover, their high Stokes shift, which limits re-absorbance phenomenon, and the high stability to ambient condition and sun irradiation, suggest their use in solar absorbing devices. During my PhD I performed deep structural investigation using synchrotron radiation after an optimization of the material synthesis; then, I worked on their exfoliation leading to the formation of very homogeneous nanosheets.
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Seminko, V. V., Yu V. Malyukin, and A. A. Masalov. "Spectroscopically detected segregation of Pr3+ ions in Y2SiO5 nanocrystals." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35434.

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Анотація:
Segregation of Pr3+ ions in Y2SiO5:Pr3+ nanocrystals was revealed by means of spectroscopic techniques. Increase of doped ions concentration in the near-surface layer of Y2SiO5:Pr3+ nanocrystals was confirmed by modification of luminescence spectra with the heat treatment temperature. Relaxation of excess elastic stresses created by Pr3+ ions with volumes greater than volume of regular Y3+ ion was determined to be the main cause of observed effects. Theoretical estimations clearly confirm the preliminary predictions. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35434
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4

Wilkinson, Andrew Richard. "The optical properties of silicon nanocrystals and the role of hydrogen passivation /." View thesis entry in Australian Digital Program, 2006. http://thesis.anu.edu.au/public/adt-ANU20060202.111537/index.html.

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Williams, Diane Keith. "Particle Size Dependence on the Luminescence Spectra of Eu3+:Y2O3 and Eu3+:CaO." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/29719.

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Анотація:
Since the Eu3+ ion can occupy different cation sites in a host material, it can serve as a useful probe of nanocrystalline structures to gain more insight into the structural changes that can occur when the particle size is reduced from the bulk to nanometer regime. The use of laser spectroscopy to probe two nanocrystalline structures, Eu3+:Y2O3 and Eu3+:CaO, was investigated. The nanocrystalline structures were prepared by the laser-vaporization-gas-phase condensation of the bulk oxides. The particle size distribution and dominant particle diameters of the nanocrystals were determined by transmission electron microscopy. The particle size dependency results of Eu3+:Y2O3 revealed three distinct phases: (1) the sharp lines of the monoclinic Y2O3 were dominant in the larger particles; (2) the C2 site of the cubic phase, which appears in the smaller particles; and (3) the amorphous phase that increases in intensity as the particle size decreases. The observation of distinct spectral lines from the monoclinic phase confirms the presence of a crystalline phase for all of particle sizes studied. The site-selective results of various concentrations of 13-nm Eu3+:CaO showed that the laser-vaporization-gas-phase condensation method of preparation produced two europium-containing phases at most concentrations: cubic CaO and monoclinic Eu2O3. Results showed that the monoclinic Eu2O3 phase could be reduced by 95% by annealing at 800 0C for 30 minutes without particle growth. Since the Eu3+ ion and the Y3+ ion are isovalent, the substitution of a Eu3+ ion into Y2O3 is considered a trivial case of extrinsic disorder since the impurity is neutral relative to a perfect crystal1. As a result, it is not necessary to have any other defects present in the crystals to maintain charge neutrality. With Eu3+:CaO, the dopant and host cation charges are different and therefore the dopant distribution can be investigated by site-selective spectroscopy. Since the experimental dopant distribution results for nanocrystalline Eu3+:CaO were inconclusive, a model to predict the theoretical change in the dopant distribution in Eu3+:CaO as a function of particle size was developed. The model predicts that the defect chemistry is affected when the particle size is approximately 50 nm and smaller.
Ph. D.
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6

Vezzoli, S. "EXPERIMENTAL STUDY OF NANOCRYSTALS AS SINGLE PHOTON SOURCES." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/222688.

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Wet-chemically synthesized colloidal nanocrystals are promising single photon emitters at room temperature, due to the strong quantum confinement induced by the small dimensions. However, their applications have been so far limited by two main drawbacks: the blinking of their photo-luminescence and a non-polarized emission. This manuscript is consecrated to the study of the optical properties of a particular type of colloidal nanocrystals, called dot-in-rod (DR), in which a spherical CdSe core is surrounded by a rod-like CdS shell. We demonstrate for the first time a suppression of the blinking in thick shell DRs. In contrast to spherical nanocrystals, we show that it can be obtained while keeping a good quality of the single photon emission and a high degree of linear polarization. A complete room-temperature characterization of the optical, and especially quantum optical, properties of DRs is provided for several geometrical parameters. In particular, an original approach, based on an ensemble photoluminescence measurement, is developed to assess the quality of a sample of nanocrystals as single photon sources. By studying single DRs in a confocal microscope, we analyze the influence of the core size and of the shell thickness and length on the photon anti-bunching, radiative lifetime and polarization of the emission. This systematic study brings a contribution to the understanding of the interaction processes of the confined carriers in semiconductor nanocrystals. The interplay of radiative and non-radiative recombinations and, in particular, the role of the Auger effect in the photo-luminescence blinking and in the emission of non-classical light are deeply investigated.
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7

La, Rosa Marcello. "Development of luminescent semiconductor nanocrystals (Quantum Dots) for photoinduced applications." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0591/document.

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Анотація:
Cette thèse s’est focalisée sur le développement de nanocristaux semi-conducteurs luminescents, i.e. des boîtes quantiques (quantum dots, QDs), pour des applications photo-induites. Ces nanomatériaux possèdent des propriétés optiques très intéressantes qui dépendent de leur taille et sont prometteurs pour des applications dans divers domaines.Les QD sont généralement hydrophobes mais de nombreuses applications intéressantes requiert une compatibilité avec l'eau ou du moins avec un environnement polaire. Cela, nécessite donc un traitement post-synthétique afin de modifier leur solubilité.Au cours de cette thèse, une nouvelle méthode pour transférer les QDs d'un solvant apolaire vers un solvant polaire a été développée en les fonctionnalisant avec l'acide lipoïque, un tensioactif complexant.L'acide lipoïque est une molécule chirale générant donc un effet de dichroïsme induit qui a pu être étudier, ainsi que sa dépendance vis-à-vis la taille des nanocristaux.Un objectif clef de ces recherches était le développement de QDs présentant un transfert d'énergie électronique réversible (REET). Il s’agit d’un transfert d'énergie bidirectionnel entre les QDs photoexcités et des unités chromophores appropriées fixées sur leur surface, dont la conséquence la plus importante est l'allongement de la durée de vie de luminescence du QD.Enfin, un nouveau protocole pour le dépôt de QDs chargés sur un substrat vitreux localement polarisé a été développé en collaboration avec le Dr Marc Dussauze de l'Université de Bordeaux
This thesis focuses on the development of luminescent semiconductor nanocrystals quantum dots (QDs) for photoinduced applications. QDs are promising nanomaterials with size-dependent optical properties and are attractive for applications in several fields.However, QDs are commonly hydrophobic and many interesting applications require their compatibility with water or at least with a polar environment, meaning a post-synthetic treatment is required to confer a different solubility.During these studies, a new method for transferring QDs from an apolar solvent to another one polar has been successfully developed, by exploiting lipoic acid, as a versatile surface capping agent. Moreover, lipoic acid is a chiral molecule so a possible induced dichroism effect has been also investigated, as well as its dependence on the size of nanocrystals.A major aim of this research was the development of QDs exhibiting reversible electronic energy transfer (REET). Such a process is a bidirectional energy transfer between the photoexcited QDs and suitable chromophoric units attached on their surface, whose most important consequence is the elongation of the luminescence lifetime of the QD. Strong experimental evidence for REET and accompanying modifications of the photophysical properties has been obtained. Such a process to our knowledge has never been observed in QD-based systems.Finally, a novel protocol for depositing charged QDs on a locally polarized glassy substrate has been developed in collaboration with Dr. Marc Dussauze of the University of Bordeaux
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Schnabel, Manuel. "Silicon nanocrystals embedded in silicon carbide for tandem solar cell applications." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:da5bbb64-0bcd-4807-a9f3-4ff63a9ca98d.

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Tandem solar cells are potentially much more efficient than the silicon solar cells that currently dominate the market but require materials with different bandgaps. This thesis presents work on silicon nanocrystals (Si-NC) embedded in silicon carbide (SiC), which are expected to have a higher bandgap than bulk Si due to quantum confinement, with a view to using them in the top cell of a tandem cell. The strong photoluminescence (PL) of precursor films used to prepare Si-NC in SiC (Si-NC/SiC) was markedly reduced upon Si-NC formation due to simultaneous out-diffusion of hydrogen that passivated dangling bonds. This cannot be reversed by hydrogenation and leads to weak PL that is due to, and limited by, non-paramagnetic defects, with an estimated quantum yield of ≤5×10-7. Optical interference was identified as a substantial artefact and a method proposed to account for this. Majority carrier transport was found to be Ohmic at all temperatures for a wide range of samples. Hydrogenation decreases dangling bond density and increases conductivity up to 1000 times. The temperature-dependence of conductivity is best described by a combination of extended-state and variable-range hopping transport where the former takes place in the Si nanoclusters. Furthermore, n-type background doping by nitrogen and/or oxygen was identified. In the course of developing processing steps for Si-NC-based tandem cells, a capping layer was developed to prevent oxidation of Si-NC/SiC, and diffusion of boron and phosphorus in nanocrystalline SiC was found to occur via grain boundaries with an activation energy of 5.3±0.4 eV and 4.4±0.7 eV, respectively. Tandem cells with a Si-NC/SiC top cell and bulk Si bottom cell were prepared that exhibited open-circuit voltages Voc of 900 mV and short-circuit current densities of 0.85 mAcm-2. Performance was limited by photocurrent collection in the top cell; however, the Voc obtained demonstrates tandem cell functionality.
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Kumar, Upkar. "Plasmon logic gates designed by modal engineering of 2-dimensional crystalline metal cavities." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30170/document.

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Анотація:
L'objectif principal de cette thèse est de concevoir, fabriquer et caractériser les dispositifs plasmoniques basés sur les cavités métalliques bidimensionnelles monocristallines pour le transfert d'information et la réalisation d'opérations logiques. Les fonctionnalités ciblées émergent de l'ingénierie spatiale et spectrale de résonances plasmon d'ordre supérieur supportées par ces cavités prismatiques. Les nouveaux éléments étudiés dans cette thèse ouvrent la voie à de nouvelles stratégies de transfert et de traitement de l'information en optique intégrée et miniaturisée. Dans un premier temps, nous caractérisons la réponse optique des nanoplaquettes d'or ultra-fines et de taille submicronique (400 à 900 nm) par spectroscopie en champ sombre. La dispersion des résonances plasmoniques d'ordre supérieur de ces cavités est mesurée et comparée avec un bon accord aux simulations obtenues par la méthode des dyades de Green (GDM). En outre, nous présentons une analyse par décomposition lorentzienne des réponses spectrales de ces nanoprismes déposés sur des minces substrats métalliques. Nous avons, par ailleurs systématiquement étudié les effets qui pourraient modifier les résonances plasmoniques par microscopie de luminescence non-linéaire, qui s'est avérée un outil efficace pour observer la densité d'états locale des plasmons de surface (SPLDOS). En particulier, nous montrons que les caractéristiques spectrale et spatiale des résonances plasmoniques d'ordre supérieur peuvent être modulées par la modification du substrat (diélectrique ou métallique), par l'insertion contrôlée d'un défaut dans la cavité ou par le couplage électromagnétique, même faible, entre les deux cavités. L'ingénierie rationnelle de la répartition spatiale des résonances confinées 2D a été appliquée à la conception de dispositifs à transmittance accordable entre deux cavités connectées. Les géométries particulières sont produites par gravure au faisceau d'ions focalisé sur des plaquettes cristallines d'or. Les dispositifs sont caractérisés par cartographie de luminescence non-linéaire en microscopie confocale et en microscopie de fuites. Cette dernière méthode offre un moyen unique d'observer la propagation du signal plasmon dans la cavité. Nous démontrons la dépendance en polarisation de la transmission plasmonique dans les composants à symétrie et géométrie adéquates. Les résultats sont fidèlement reproduits par notre outil de simulation GDM adapté à la configuration de transmission. Enfin, notre approche est appliquée à la conception et à la fabrication d'une porte logique reconfigurable avec plusieurs entrées et sorties. Nous démontrons que dix des douze portes logiques possibles à 2 entrées et 1 sortie sont activable sur une même structure en choisissant les trois points d'entrée et de sortie et en ajustant le seuil de luminescence non-linéaire pour le signal de sortie
The main objective of this PhD work is to design, fabricate and characterize plasmonic devices based on highly crystalline metallic cavities for the two-dimensional information transfer and logic gate operations. First, we thoroughly characterize the optical response of ultra-thin gold colloidal cavities of sub-micronic size (400 to 900 nm) by dark- field spectroscopy (Fig. 1a). The dispersion of the high order plasmonic resonances of the cavities is measured and compared with a good agreement to simulations obtained with a numerical based on the Green Dyadic Method (GDM). We further extend our experiments to systematically tune the spectral responses of these colloidal nanoprisms in vicinity of metallic thin film substrates. A comprehensive study of these sub-micronic size cavity in bowtie antenna configuration is performed. We show a polarization-dependent field enhancement and a nanoscale field confinement at specific locations in these bowtie antennas. We systematically study the effects that could potentially affect the plasmonic resonances by non-linear photon luminescence microscopy, which has proved to be an efficient tool to observe the surface plasmon local density of states (SPLDOS). Inparticular, we show that an effective spatially and spectrally tuning of the high order plasmonic resonances can be achieved by the modification of the substrate (dielectric or metallic), by the controlled insertion of a defect inside a cavity or by the weak electromagnetic coupling between two adjacent cavities. The rational tailoring of the spatial distribution of the 2D confined resonances was applied to the design of devices with tunable plasmon transmittance between two connected cavities. The specific geometries are produced by focused ion milling crystalline gold platelets. The devices are characterized by non-linear luminescence mapping in confocal and leakage radiation microscopy techniques. The latter offers a unique way to observe propagating SPP signal over a 2D plasmonic cavity. We demonstrate the polarization-dependent mode-mediated transmittance for devices withadequate symmetry. The results are faithfully reproduced with our simulation tool based on Green dyadic method. Finally, we extend our approach to the design and fabrication of a reconfigurable logic gate device with multiple inputs and outputs. We demonstrate that 10 out of the possible 12 2-input 1-output logic gates can be implemented on the same structure by choosing the two input and the one output points. We also demonstrate reconfiguration of the device by changing polarization of the incident beam, set of input locations and threshold of the non-linear luminescence readout signal
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10

Eloi, Fabien. "Étude de la luminescence de nanocristaux semi-conducteurs couplés avec des structures plasmoniques à températures ambiante et cryogénique." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV117/document.

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Les nanocristaux semi-conducteurs colloïdaux possèdent des propriétés photo-physiques qui en font des objets de choix pour des applications variées, comme le marquage biologique, le photovoltaïque ou encore l'optique quantique. Dans cette thèse, nous étudions les modifications, introduites par des réseaux d'or, de la fluorescence de nanocristaux CdSe/CdS à coquille épaisse. Nous présentons tout d'abord les propriétés fondamentales de ces nanocristaux de CdSe/CdS puis la manière dont leurs propriétés d'émission peuvent être contrôlées par l'environnement électromagnétique, en détaillant en particulier le cas d'un couplage avec des plasmons de surface. Des simulations réalisées par nos collaborateurs du LICB dans le cadre d'un projet ANR sont ensuite comparées à nos mesures expérimentales. Nous observons que le couplage des nano-émetteurs individuels au réseau d'or permet à la fois d'accélérer l'émission spontanée et de mieux la collecter. Les structures métalliques sont optimisées pour que les améliorations détectées soient peu sensibles à la position de l'émetteur. Un effet supplémentaire est le contrôle de la polarisation de l'émission qui se révèle être fixée pa r le réseau. Nous rapportons également des changements dans la statistique temporelle d'émission des photons et notamment la suppression totale du scintillement. Les métaux étant connus pour leurs pertes ohmiques, des expériences ont été réalisées pour montrer que les pertes non radiatives qu'elles entraînent peuvent être réduites à basse température. Nous avons examiné le cas d'une surface d'or plane ainsi que des réseaux linéaires et circulaires. Enfin, une nouvelle méthode de post-traitement a été développée en parallèle. Elle permet par exemple d'étudier les variations de l'efficacité quantique bi-excitonique dans des nanocristaux enrobés d'or suivant l'état de charge de l'émetteur
Colloidal semiconductor nanocrystals are fluorescent nano-objects exhibiting discrete energy levels which justify their second appellation: quantum dots (QDs). Due to their high efficiency and ease of use, they find potential applications in a wide range of fields. Their usefulness for biological labeling, optoelectronic components in flat screens, light harvesting or quantum optics has been demonstrated by many studies. In this thesis, we use gold gratings in order to modify the emission properties of CdSe/CdS core-shell nanocrystals. After a brief presentation of their electronic and fluorescence properties, we explain how those properties can be modified by the control of the electromagnetic environment with particular care to the case of surface plasmons. We then show through experiment and simulations that those plasmons enable better collection efficiency, faster photo-luminescence decay rates, and polarized emission without being particularly restricting towards QD positioning. Changes in the emission statistics are also observed, notably total suppression of the blinking in the fluorescence intensity. Further experiments at low temperature have been realized in order to assess the importance of the gold ohmic losses. We investigated the case of a flat gold film as well as linear and circular gratings. A new post-selection method is also introduced and used to study the variations of the bi-excitonic quantum yield for nanocrystals embedded in a gold nano-resonator as a function of the ionization state of the emitter
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Книги з теми "Nanocrystals - Luminescence"

1

Yu, Lixin. Development of Luminescence Properties of Eu3+-doped Nanosized Materials. Nova Science Publishers, Incorporated, 2011.

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2

Chang, Tung-Wah Frederick. Luminescence and energy transfer excitation of infrared colloidal semiconductor nanocrystals: Y Tung-Wah Frederick Chang. 2006.

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Частини книг з теми "Nanocrystals - Luminescence"

1

Charra, Fabrice. "Scanning Tunneling Luminescence from Metal Nanoparticles." In Nanocrystals Forming Mesoscopic Structures, 231–50. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607587.ch9.

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2

Murotani, Hideaki, Yoichi Yamada, Daisuke Nakamura, and Tatsuo Okada. "Time and Spatially Resolved Luminescence Spectroscopy of ZnO Nanostructures." In ZnO Nanocrystals and Allied Materials, 195–216. New Delhi: Springer India, 2013. http://dx.doi.org/10.1007/978-81-322-1160-0_9.

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3

Zhang, Fan. "Upconversion Luminescence of Lanthanide Ion-Doped Nanocrystals." In Photon Upconversion Nanomaterials, 73–119. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-45597-5_3.

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4

Millers, Donats, Larisa Grigorjeva, Witold Łojkowski, and A. Opalińska. "Luminescence of ZrO2 Nanocrystals." In Solid State Phenomena, 103–8. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/3-908451-10-8.103.

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5

Freedhoff, M. I., W. Chen, J. M. Rehm, C. Meyers, A. Marchetti, and G. Mclendon. "Luminescence Properties of Silver Bromide: From Nanocrystals to Microcrystals." In Fine Particles Science and Technology, 281–93. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0259-6_21.

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6

Pankratov, V., Larisa Grigorjeva, Donats Millers, Tadeusz Chudoba, Robert Fedyk, and Witold Łojkowski. "Time-Resolved Luminescence Characteristics of Cerium Doped YAG Nanocrystals." In Solid State Phenomena, 173–78. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/3-908451-38-8.173.

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7

He, Ying, K. Ma, L. Bi, J. Y. Feng, and Q. L. Wu. "Strong Near-Infrared Luminescence from NiSi2-Passivated Silicon Nanocrystals Embedded in SiOx Films." In Key Engineering Materials, 655–57. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-410-3.655.

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8

de Farias Soares, Alvaro, Sonia Hatsue Tatumi, and Lilia Coronato Courrol. "TL, OSL, and PL Properties of Zinc Oxide Nanocrystals." In Luminescent Nanomaterials, 97–127. New York: Jenny Stanford Publishing, 2022. http://dx.doi.org/10.1201/9781003277385-2.

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9

Sugimoto, Hiroshi, and Minoru Fujii. "Near-infrared luminescent colloidal silicon nanocrystals." In Silicon Nanomaterials Sourcebook, 399–412. Boca Raton, FL: CRC Press, Taylor & Francis Group, [2017] | Series: Series in materials science and engineering: CRC Press, 2017. http://dx.doi.org/10.4324/9781315153544-19.

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10

Silvi, Serena, Massimo Baroncini, Marcello La Rosa, and Alberto Credi. "Interfacing Luminescent Quantum Dots with Functional Molecules for Optical Sensing Applications." In Photoactive Semiconductor Nanocrystal Quantum Dots, 61–87. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-51192-4_3.

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Тези доповідей конференцій з теми "Nanocrystals - Luminescence"

1

Andersson-Engels, Stefan, Can Xu, Johan Axelsson, Haichun Liu, Pontus Svenmarker, Gabriel Somesfalean, and Zhiguo Zhang. "Upconverting Luminescence Nanocrystals for Biomedical Applications." In Asia Communications and Photonics Conference and Exhibition. Washington, D.C.: OSA, 2009. http://dx.doi.org/10.1364/acp.2009.thgg2.

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2

Oron, Dan. "Luminescence Upconversion in Designer Semiconductor Nanocrystals." In nanoGe Fall Meeting 2018. València: Fundació Scito, 2018. http://dx.doi.org/10.29363/nanoge.fallmeeting.2018.019.

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3

Goffard, Julie, Davy Gérard, Patrice Miska, Anne-Laure Baudrion, Michel Vergnat, and Jérôme Plain. "Plasmon-enhanced luminescence from silicon nanocrystals." In CLEO: QELS_Fundamental Science. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/cleo_qels.2013.qf2a.4.

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4

Oron, Dan. "Luminescence Upconversion in Designer Semiconductor Nanocrystals." In nanoGe Fall Meeting 2018. València: Fundació Scito, 2018. http://dx.doi.org/10.29363/nanoge.nfm.2018.019.

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5

Patle, Anita, R. R. Patil, and S. V. Moharil. "Luminescence study in Ce3+ doped SrF2 nanocrystals." In INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC 2015): Proceeding of International Conference on Condensed Matter and Applied Physics. Author(s), 2016. http://dx.doi.org/10.1063/1.4946404.

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6

Tsybeskov, L., K. L. Moore, S. P. Duttagupta, K. D. Hirschman, D. G. Hall, and P. M. Fauchet. "Fabrication and Luminescence of Large Si Nanocrystals." In Chemistry and Physics of Small-Scale Structures. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/cps.1997.ctub.6.

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The photoluminescence (PL) in crystalline silicon (c-Si) has been investigated during the last decades. Recent interest has focused on the visible PL that is observed in Si nanoclusters and in porous Si (PSi), the infrared PL in silicon-germanium superlattices, and the subgap PL due to impurities in c-Si [1]. Band edge PL in bulk Si is inefficient and usually observed only at low temperatures because c-Si has an indirect bandgap. The electroluminescence (EL) is as inefficient as the photoluminescence (PL) and, in addition, the EL is quenched by an electric field E ≥ 104 V/cm due to field-induced dissociation of the exciton. In this work we report a significant increase of the Si band edge photoluminescence and electroluminescence and its unexpectedly weak temperature dependence in large Si nanocrystals produced by the recrystallization of oxidized porous Si.
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7

Lounis, Brahim. "Single semiconductor nanocrystals luminescence decay and photon statistics." In International Quantum Electronics Conference. Washington, D.C.: OSA, 2004. http://dx.doi.org/10.1364/iqec.2004.ithj3.

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8

Diener, Joachim, Dmitri I. Kovalev, Gennadi Polisski, and Frederick Koch. "Polarization properties of the luminescence from silicon nanocrystals." In Fifth International Conference on Material Science and Material Properties for Infrared Optoelectronics, edited by Fiodor F. Sizov. SPIE, 2001. http://dx.doi.org/10.1117/12.417772.

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Bacher, Gerd, Alexander Schmitz, L. Leander Schaberg, Oliver Pfingsten, Julian Klein, Federico Montanarella, Maryna I. Bodnarchuk, and Maksym Kovalenko. "Polarized Luminescence from Single Lead Halide Perovskite Nanocrystals." In MATSUS23 & Sustainable Technology Forum València (STECH23). València: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2022. http://dx.doi.org/10.29363/nanoge.matsus.2023.347.

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10

Xue, Xiaojie, Takenobu Suzuki, Rajanish N. Tiwari, Masamichi Yoshimura, and Yasutake Ohishi. "Size-dependent Luminescence of Nd3+-doped LiYF4 Nanocrystals." In Frontiers in Optics. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/fio.2013.ftu3a.19.

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