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Journal articles on the topic 'Semiconductor nanocrystals'

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Author: Grafiati

Published: 4 June 2021

Last updated: 7 September 2023

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1

Milliron, Delia J., Ilan Gur, and A. Paul Alivisatos. "Hybrid Organic–Nanocrystal Solar Cells." MRS Bulletin 30, no. 1 (January 2005): 41–44. http://dx.doi.org/10.1557/mrs2005.8.

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AbstractRecent results have demonstrated that hybrid photovoltaic cells based on a blend of inorganic nanocrystals and polymers possess significant potential for low-cost, scalable solar power conversion. Colloidal semiconductor nanocrystals, like polymers, are solution processable and chemically synthesized, but possess the advantageous properties of inorganic semiconductors such as a broad spectral absorption range and high carrier mobilities. Significant advances in hybrid solar cells have followed the development of elongated nanocrystal rods and branched nanocrystals, which enable more effective charge transport. The incorporation of these larger nanostructures into polymers has required optimization of blend morphology using solvent mixtures. Future advances will rely on new nanocrystals, such as cadmium telluride tetrapods, that have the potential to enhance light absorption and further improve charge transport. Gains can also be made by incorporating application-specific organic components, including electroactive surfactants which control the physical and electronic interactions between nanocrystals and polymer.

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2

Lin, Weyde M. M., Maksym Yarema, Mengxia Liu, Edward Sargent, and Vanessa Wood. "Nanocrystal Quantum Dot Devices: How the Lead Sulfide (PbS) System Teaches Us the Importance of Surfaces." CHIMIA International Journal for Chemistry 75, no. 5 (May 28, 2021): 398–413. http://dx.doi.org/10.2533/chimia.2021.398.

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Semiconducting thin films made from nanocrystals hold potential as composite hybrid materials with new functionalities. With nanocrystal syntheses, composition can be controlled at the sub-nanometer level, and, by tuning size, shape, and surface termination of the nanocrystals as well as their packing, it is possible to select the electronic, phononic, and photonic properties of the resulting thin films. While the ability to tune the properties of a semiconductor from the atomistic- to macro-scale using solution-based techniques presents unique opportunities, it also introduces challenges for process control and reproducibility. In this review, we use the example of well-studied lead sulfide (PbS) nanocrystals and describe the key advances in nanocrystal synthesis and thin-film fabrication that have enabled improvement in performance of photovoltaic devices. While research moves forward with novel nanocrystal materials, it is important to consider what decades of work on PbS nanocrystals has taught us and how we can apply these learnings to realize the full potential of nanocrystal solids as highly flexible materials systems for functional semiconductor thin-film devices. One key lesson is the importance of controlling and manipulating surfaces.

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3

Shen, Hao, Huabao Shang, Yuhan Gao, Deren Yang, and Dongsheng Li. "Efficient Sensitized Photoluminescence from Erbium Chloride Silicate via Interparticle Energy Transfer." Materials 15, no. 3 (January 30, 2022): 1093. http://dx.doi.org/10.3390/ma15031093.

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In this study, we prepare Erbium compound nanocrystals and Si nanocrystal (Si NC) co-embedded silica film by the sol-gel method. Dual phases of Si and Er chloride silicate (ECS) nanocrystals were coprecipitated within amorphous silica. Effective sensitized emission of Er chloride silicate nanocrystals was realized via interparticle energy transfer between silicon nanocrystal and Er chloride silicate nanocrystals. The influence of density and the distribution of sensitizers and Er compounds on interparticle energy transfer efficiency was discussed. The interparticle energy transfer between the semiconductor and erbium compound nanocrystals offers some important insights into the realization of efficient light emission for silicon-based integrated photonics.

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4

Alivisatos, A. Paul. "Semiconductor Nanocrystals." MRS Bulletin 20, no. 8 (August 1995): 23–32. http://dx.doi.org/10.1557/s0883769400045073.

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The following is an edited transcript of the presentation given by A. Paul Alivisatos, recipient of the Outstanding Young Investigator Award, at the 1995 MRS Spring Meeting in San Francisco.The work I will describe on semiconductor nanocrystals started with the realization that it is possible to precipitate a semiconductor out of an organic liquid. We can precipitate out a semiconductor as a colloid—a very small-sized semiconductor with reduced dimensionality—that will show large, quantum size effects. A dream at that time was to make an electronic material by such a process in a liquid beaker, by starting with an organic fluid and somehow injecting something into the fluid to make very small particles, which we could use in electronics. The materials we use in electronics today have perfect crystalline order. We are able to put in dopants very specifically, or control precisely their arrangements in space in enormously complicated ways. The level of purity of electronic materials is so high that making an electronic material in a wet chemistry approach seems almost impossible. If, in addition, we specify that the size must be controlled precisely, we recognize the project is a problem for basic research, yet not one ready for applications. Many fundamental problems arise if we try to make semiconductor particles, in a liquid, of such high quality that they can be used as electronic materials.

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5

Stein, Benjamin P. "Semiconductor nanocrystals." Physics Today 57, no. 6 (June 2004): 9. http://dx.doi.org/10.1063/1.4796571.

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6

SAPRA, SAMEER, RANJANI VISWANATHA, and D. D. SARMA. "ELECTRONIC STRUCTURE OF SEMICONDUCTOR NANOCRYSTALS: AN ACCURATE TIGHT-BINDING DESCRIPTION." International Journal of Nanoscience 04, no. 05n06 (October 2005): 893–99. http://dx.doi.org/10.1142/s0219581x05003851.

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We report a quantitatively accurate description of the electronic structure of semiconductor nanocrystals using the sp3d5 orbital basis with the nearest neighbor and the next nearest neighbor interactions. The use of this model for II–VI and III–V semiconductors is reviewed in article. The excellent agreement of the theoretical predictions with the experimental results establishes the feasibility of using this model for semiconductor nanocrystals.

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7

Utterback, James K., Jesse L. Ruzicka, Helena R. Keller, Lauren M. Pellows, and Gordana Dukovic. "Electron Transfer from Semiconductor Nanocrystals to Redox Enzymes." Annual Review of Physical Chemistry 71, no. 1 (April 20, 2020): 335–59. http://dx.doi.org/10.1146/annurev-physchem-050317-014232.

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This review summarizes progress in understanding electron transfer from photoexcited nanocrystals to redox enzymes. The combination of the light-harvesting properties of nanocrystals and the catalytic properties of redox enzymes has emerged as a versatile platform to drive a variety of enzyme-catalyzed reactions with light. Transfer of a photoexcited charge from a nanocrystal to an enzyme is a critical first step for these reactions. This process has been studied in depth in systems that combine Cd-chalcogenide nanocrystals with hydrogenases. The two components can be assembled in close proximity to enable direct interfacial electron transfer or integrated with redox mediators to transport charges. Time-resolved spectroscopy and kinetic modeling have been used to measure the rates and efficiencies of the electron transfer. Electron transfer has been described within the framework of Marcus theory, providing insights into the factors that can be used to control the photochemical activity of these biohybrid systems. The range of potential applications and reactions that can be achieved using nanocrystal–enzyme systems is expanding, and numerous fundamental and practical questions remain to be addressed.

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8

Lazzari, Stefano, Milad Abolhasani, and Klavs F. Jensen. "Modeling of the formation kinetics and size distribution evolution of II–VI quantum dots." Reaction Chemistry & Engineering 2, no. 4 (2017): 567–76. http://dx.doi.org/10.1039/c7re00068e.

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9

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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10

Yang, C. C., and Qing Jiang. "Size Effect on the Bandgap of Semiconductor Nanocrystals." Solid State Phenomena 121-123 (March 2007): 1069–72. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.1069.

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The size-dependent valence-conduction bandgap of semiconductor nanocrystals are predicted based on a model for size-dependent cohesive energy, without any adjustable parameter. The model predicts an increase of the bandgap of semiconductors with decreasing crystalline sizes. It is found that the model predictions are in good agreement with the available experimental results for Si, ZnS, ZnSe, CdS, and CdSe nanocrystals.

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11

Yang, C. C., and S. Li. "Size Dependence of Optical Properties in Semiconductor Nanocrystals." Key Engineering Materials 444 (July 2010): 133–62. http://dx.doi.org/10.4028/www.scientific.net/kem.444.133.

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An extension of the classic thermodynamic theory to nanometer scale has generated a new interdisciplinary theory - nanothermodynamics. It is the critical tool for the investigation of the size-dependent physicochemical properties in nanocrystals. A simple and unified nanothermodynamic model for the melting temperature of nanocrystals has been established based on Lindemann’s criterion for the melting, Mott’s expression for the vibrational melting entropy, and Shi’s model for the size dependence of the melting point. The developed model has been extensively verified in calculating a variety of size- and dimensionality-dependent phase transition functions of nanocrystals. In this work, such a model was extended to explain the underlying mechanism behind the bandgap energy enhancement and Raman red shifts in semiconductor nanocrystals by (1) investigating the crystal size r, dimensionality d, and constituent stoichiometry x dependences of bandgap energies Eg in semiconductor quantum dots (QDs) and quantum wires (QWs); and (2) revealing the origin of size effect on the Raman red shifts in low dimensional semiconductors by considering the thermal vibration of atoms. For Eg, it is found that: (1) Eg increases with a decreasing r for groups IV, III-V and II-VI semiconductors and the quantum confinement effect is pronounced when r becomes comparable to the exciton radius; (2) the ratio of Eg(r, d)QWs/Eg(r, d)QDs is size-dependent, where Eg(r, d) denotes the change in bandgap energy; (3) the crystallographic structure (i.e. zinc-blende and wurtzite) effect on Eg of III-V and II-VI semiconductor nanocrystals is limited; and (4) for both bulk and nanosized III-V and II-VI semiconductor alloys, the composition effects on Eg are substantial, having a common nonlinear (bowing) relationship. For the Raman red shifts, the lower limit of vibrational frequency was obtained by matching the calculation results of the shifts with the experimental data of Si, InP, CdSe, CdS0.65Se0.35, ZnO, CeO2, as well as SnO2 nanocrystals. It shows that: (1) the Raman frequency (r) decreases as r decreases in both narrow and wide bandgap semiconductors; (2) with the same r, the sequence of size effects on (r) from strong to weak is nanoparticles, nanowires, and thin films; and (3) the Raman red shift is caused by the size-induced phonon confinement effect and surface relaxation. These results are consistent with experimental findings and may provide new insights into the size, dimensionality, and composition effects on the optical properties of semiconductors as well as fundamental understanding of high-performance nanostructural semiconductors towards their applications in optoelectronic devices.

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12

Wang, Yu, Xinxing Peng, Alex Abelson, Penghao Xiao, Caroline Qian, Lei Yu, Colin Ophus, et al. "Dynamic deformability of individual PbSe nanocrystals during superlattice phase transitions." Science Advances 5, no. 6 (June 2019): eaaw5623. http://dx.doi.org/10.1126/sciadv.aaw5623.

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The behavior of individual nanocrystals during superlattice phase transitions can profoundly affect the structural perfection and electronic properties of the resulting superlattices. However, details of nanocrystal morphological changes during superlattice phase transitions are largely unknown due to the lack of direct observation. Here, we report the dynamic deformability of PbSe semiconductor nanocrystals during superlattice phase transitions that are driven by ligand displacement. Real-time high-resolution imaging with liquid-phase transmission electron microscopy reveals that following ligand removal, the individual PbSe nanocrystals experience drastic directional shape deformation when the spacing between nanocrystals reaches 2 to 4 nm. The deformation can be completely recovered when two nanocrystals move apart or it can be retained when they attach. The large deformation, which is responsible for the structural defects in the epitaxially fused nanocrystal superlattice, may arise from internanocrystal dipole–dipole interactions.

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13

Manna, Liberato, Osman M. Bakr, Sergio Brovelli, and Hongbo Li. "Perovskite Semiconductor Nanocrystals." Energy Material Advances 2022 (February 22, 2022): 1–2. http://dx.doi.org/10.34133/2022/9865891.

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14

Erwin, Steven C., Lijun Zu, Michael I. Haftel, Alexander L. Efros, Thomas A. Kennedy, and David J. Norris. "Doping semiconductor nanocrystals." Nature 436, no. 7047 (July 2005): 91–94. http://dx.doi.org/10.1038/nature03832.

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15

Telford, Mark. "Doping semiconductor nanocrystals." Materials Today 8, no. 9 (September 2005): 10. http://dx.doi.org/10.1016/s1369-7021(05)71063-4.

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16

Dorfs, Dirk, and Alexander Eychmüller. "Multishell Semiconductor Nanocrystals." Zeitschrift für Physikalische Chemie 220, no. 12 (December 2006): 1539–52. http://dx.doi.org/10.1524/zpch.2006.220.12.1539.

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17

Lawrence, Katie N., Merrell A. Johnson, Sukanta Dolai, Amar Kumbhar, and Rajesh Sardar. "Solvent-like ligand-coated ultrasmall cadmium selenide nanocrystals: strong electronic coupling in a self-organized assembly." Nanoscale 7, no. 27 (2015): 11667–77. http://dx.doi.org/10.1039/c5nr02038g.

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Strong inter-nanocrystal electronic coupling is demonstrated between short chain poly(ethylene glycol) thiolate-coated ultrasmall (<2.5 nm in diameter) CdSe semiconductor nanocrystals both in the colloidal state and as dry films on solid surfaces.

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18

Zhang, Ya Ting, and Jian Quan Yao. "Photoconductive Properties of MEH-PPV/InP Nanocomposite Diode." Advanced Materials Research 531 (June 2012): 31–34. http://dx.doi.org/10.4028/www.scientific.net/amr.531.31.

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InP nanocrystals were prepared by an economic chemical reaction. A very high density of surface states is found at 0.5 eV below the intrinsic conductive band edge. Mixing these InP nanocrystals with MEH-PPV, obtained the composite. Devices with structure ITO/composite(MEH-PPV)/Al were fabricated and investigated. Photocurrent spectra showed that the interface between a conjugated polymer and a semiconductor nanocrystal can be used to provide efficient charge separation for neutral excitons on both the ground states and excited ones. Incorporation of nanocrystals, the conductivity of diode shows large improvements.

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19

Gerdes, Frauke, Eugen Klein, Sascha Kull, Mohammad Mehdi Ramin Moayed, Rostyslav Lesyuk, and Christian Klinke. "Halogens in the Synthesis of Colloidal Semiconductor Nanocrystals." Zeitschrift für Physikalische Chemie 232, no. 9-11 (August 28, 2018): 1267–80. http://dx.doi.org/10.1515/zpch-2018-1164.

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Abstract In this review, we highlight the role of halogenated compounds in the colloidal synthesis of nanostructured semiconductors. Halogen-containing metallic salts used as precursors and halogenated hydrocarbons used as ligands allow stabilizing different shapes and crystal phases, and enable the formation of colloidal systems with different dimensionality. We summarize recent reports on the tremendous influence of these compounds on the physical properties of nanocrystals, like field-effect mobility and solar cell performance and outline main analytical methods for the nanocrystal surface control.

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20

Pascazio, Roberta, Juliette Zito, and Ivan Infante. "An Overview of Computational Studies on Colloidal Semiconductor Nanocrystals." CHIMIA International Journal for Chemistry 75, no. 5 (May 28, 2021): 427–34. http://dx.doi.org/10.2533/chimia.2021.427.

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In the last two decades, colloidal semiconductor nanocrystals have emerged as a phenomenal research topic due to their size-dependent optoelectronic properties and to their outstanding versatility in many technological applications. In this review, we provide an historical account of the most relevant computational works that have been carried out to understand atomistically the electronic structure of these materials, including the main requirements needed for the preparation of nanocrystal models that align well with the experiments. We further discuss how the advancement of these computational tools has affected the analysis of these nanomaterials over the years. We focus our review on the three main families of colloidal semiconductor nanocrystals: group II-VI and IV-VI metal chalcogenides, group III-V metal pnictogenides and metal halides, in particular lead-based halide perovskites. We discuss the most recent research frontiers and outline the future outlooks expected in this field from a computational perspective.

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21

Harfenist, S. A., Z. L. Wang, T. G. Schaaff, and R. L. Whettent. "A BCC Superlattice of Passivated Gold Nanocrystals." Microscopy and Microanalysis 4, S2 (July 1998): 716–17. http://dx.doi.org/10.1017/s1431927600023709.

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A recent development in the study of nanocrystalline materials has been the self-assembly of passivated nanometer scale building blocks into larger, well ordered structures reaching the micron scale. Nanocrystal supercrystals (NCS) have been observed in metallic, semiconductor, and magnetic materials. In most cases the nanocrystals (NXs) are encapsulated in some inert medium that effectively protects the nanocrystal core and its unique electronic and optical properties. Here we describe the self-assembly of gold nanocrystals (∼4.5 nm core diameter), passivated with hexanethiol self-assembled-monolayers into ordered regions exhibiting a body-centered-cubic (bcc) superstructure. Transmission Electron Microscopy (TEM) imaging and Electron Diffraction (ED) experiments were used to characterize the NCSs and their resulting superstructures.A large agglomeration of NCSs can be seen in figure 1. One can clearly see regions of periodicity within the nanocrystal aggregation.

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22

Mohammadrezaee, Mohammad, Naser Hatefi-Kargan, and Ahmadreza Daraei. "Enhancing crystal quality and optical properties of GaN nanocrystals by tuning pH of the synthesis solution." Zeitschrift für Naturforschung A 75, no. 6 (May 26, 2020): 551–56. http://dx.doi.org/10.1515/zna-2019-0378.

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AbstractGallium nitride nanocrystals as a wide bandgap semiconductor material for optoelectronic applications can be synthesized using chemical methods. In this research using co-precipitation and nitridation processes gallium nitride nanocrystals have been synthesized, and by tuning pH of the synthesis solution at the co-precipitation step, crystal quality and optical property of the resultant gallium nitride nanocrystals have been enhanced. Gallium nitride nanocrystal samples were synthesized using solutions with pH values of 2.1, 4.8, 7.8, and 9.0, and then nitridation at 950 °C under the flow of ammonia gas. The synthesized nanocrystal samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence techniques. The XRD data show that the nanocrystals have hexagonal wurtzite crystal structure, and using Scherer’s equation the sizes of the synthesized nanocrystals are 23.6, 26.6, 19.7, and 10.4 nm for the samples synthesized using the solutions with pH values of 2.1, 4.8, 7.8, and 9.0 respectively. The sizes of the nanocrystals obtained from SEM images are larger than the values obtained using Scherer’s equation, due to the aggregation of nanocrystals. EDX spectra show that pH of the synthesis solution affects the elemental stoichiometry of the gallium nitride nanocrystals. We obtained better stoichiometry for the nanocrystal sample synthesized using solution with the pH of 4.8. Photoluminescence spectra show that for this sample the emission intensity is higher than the others.

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23

Craievich, A. F., O. L. Alves, and L. C. Barbosa. "Formation and Growth of Semiconductor PbTe Nanocrystals in a Borosilicate Glass Matrix." Journal of Applied Crystallography 30, no. 5 (October 1, 1997): 623–27. http://dx.doi.org/10.1107/s0021889897001799.

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Pb- and Te-doped borosilicate glasses are transformed by appropriate heat treatment into a composite material consisting of a vitreous matrix in which semiconductor PbTe nanocrystals are embedded. This composite exhibits interesting non-linear optical properties in the infrared region, in the range 10–20 000 Å. The shape and size distribution of the nanocrystals and the kinetics of their growth were studied by small-angle X-ray scattering (SAXS) during in situ isothermal treatment at 923 K. The experimental results indicate that nanocrystals are nearly spherical and have an average radius increasing from 16 to 33 Å after 2 h at 923 K, the relative size dispersion being time-invariant and approximately equal to 8%. This investigation demonstrates that the kinetics of nanocrystal growth are governed by the classic mechanism of atomic diffusion. The radius of nanocrystals, deduced by applying the simple Efros & Efros [Sov. Phys. Semicond. (1982), 16, 772–775] model using the energy values corresponding to the exciton peaks of optical absorption spectra, does not agree with the average radius determined by SAXS.

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24

Nakamura, Y., T. Ishibe, T. Taniguchi, T. Terada, R. Hosoda, and Sh Sakane. "Semiconductor Nanostructure Design for Thermoelectric Property Control." International Journal of Nanoscience 18, no. 03n04 (March 28, 2019): 1940036. http://dx.doi.org/10.1142/s0219581x19400362.

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We present the methodologies for developing high-performance thermoelectric materials using nanostructured interfaces by reviewing our three studies and giving the new aspect of nanostructuring results. (1) Connected Si nanocrystals exhibited ultrasmall thermal conductivity. The drastic thermal conductivity reduction was brought by phonon confinement and phonon scattering. Here, we present discussion about the new aspect for phonon transport: not only nanocrystal size but also shape can contribute to thermal conductivity reduction. (2) Si films including Ge nanocrystals demonstrated that phonon and carrier conductions were independently controlled in the films, where carriers were easily transported through the interfaces between Si and Ge, while phonons could be effectively scattered at the interfaces. (3) Embedded-ZnO nanowire structure demonstrated the simultaneous realization of power factor increase and thermal conductivity reduction. The [Formula: see text] increase was caused by the interface-dominated carrier transport. The nanowire interfaces also worked as phonon scatterers, resulting in the thermal conductivity reduction.

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25

Yang, Fuqian. "Kinetic analysis of the growth of semiconductor nanocrystals from the peak wavelength of photoluminescence." European Physical Journal Applied Physics 97 (2022): 20. http://dx.doi.org/10.1051/epjap/2022210286.

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Understanding the rate processes controlling the growth of semiconductor nanocrystals in liquid solutions is of great importance in tailoring the sizes of semiconductor nanocrystals for the applications in optoelectronics, bioimaging and biosensing. In this work, we establish a simple relationship between the photoluminescence (PL) peak wavelength and the growth time of semiconductor nanocrystals under the condition that the contribution of electrostatic interaction to the quantum confinement is negligible. Using this relationship and the data available in the literature for CdSe and CdSe/ZnS nanocrystals, we demonstrate the feasibility of using the PL peak wavelength to analyze the growth behavior of the CdSe and CdSe/ZnS nanocrystals in liquid solutions. The results reveal that the diffusion of monomers in the liquid solution is the dominant rate process for the growth of CdSe/ZnS nanocrystals, and the activation energy for the growth of CdSe nanocrystals in the liquid solution is ∼9 kJ/mol. The feasibility to use this approach in the analysis of the thickness growth of core–shell nanocrystals with and without mechanical stress is also discussed. Such an approach opens a new avenue to in-situ monitor/examine the growth of semiconductor nanocrystals in liquid solutions.

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Ding, Yong Ling, Hua Dong Sun, Kang Ning Sun, and Fu Tian Liu. "Water-Based Route to Synthesis of High-Quality UV-Blue Photoluminescing ZnSe/ZnS Core/Shell Quantum Dots and their Physicochemical Characterization." Key Engineering Materials 680 (February 2016): 553–57. http://dx.doi.org/10.4028/www.scientific.net/kem.680.553.

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Epitaxially overgrowing a semiconductor material with higher bandgap around the QDs has proven to be a crucial approach for improving the PL efficiency and stability of nanocrystals. In this paper, a ZnS shell was deposited around ZnSe nanocrystal cores via a noninjection approach in aqueous media. The deposition procedure conducted at 100°C in a reaction flask in the presence of the shell precursor compounds, together with the crude ZnSe nanocrystal cores and the thiol ligand glutathione. The influences of various experimental variables, including the reaction time, amount of thiourea, as well as pH value, on the growth rate and luminescent properties of the obtained core/shell nanocrystals have been systematically investigated. In comparison with the original ZnSe nanocrystals, the PL efficiency of the obtained ZnSe/ZnS core/shell nanostructures can be improved significantly with a QY up to 62.8%.

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Choi, Seong Jae, Dong Kee Yi, Jae-Young Choi, Jong-Bong Park, In-Yong Song, Eunjoo Jang, Joo In Lee, et al. "Spatial Control of Quantum Sized Nanocrystal Arrays onto Silicon Wafers." Journal of Nanoscience and Nanotechnology 7, no. 12 (December 1, 2007): 4285–93. http://dx.doi.org/10.1166/jnn.2007.884.

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Monolayer arrays of monodispersed nanocrystals (<10 nm) onto three dimensional (3D) substrates have considerable potential for various engineering applications such as highly integrated memory devices, solar cells, biosensors and photo and electro luminescent displays because of their highly integrated features with nanocrystal homogeneity. However, most reports on nanocrystal arrays have focused on two dimensional (2D) flat substrates, and the production of wafer-scale monolayer arrays is still challenging. Here we address the feasibility of arraying nanocrystal monolayers in wafer-scale onto 3D substrates. We present both metal (Pd) and semiconductor (CdSe) nanocrystals arrayed in monolayer onto trenched silicon wafers (4 inch diameter) using a facile electrostatic adsorption scheme. In particular, CdSe nanocrystal arrays in the trench well showed superior luminescent efficiency compared to those onto the protruded trench flat, due to the densely arrayed CdSe nanocrystals in the vertical direction. Furthermore, the surface coverage controllability was investigated using a 2D silicon substrate. Our approach can be applied to generate highly efficient displays, memory chips and integrated sensing devices.

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28

Rodina, A., and D. Yakovlev. "Spins in Semiconductor Nanocrystals." Priroda, no. 9 (2018): 22–31. http://dx.doi.org/10.31857/s0032874x0000887-4.

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29

Ma, Nan, Chad J. Dooley, and Shana O. Kelley. "RNA-Templated Semiconductor Nanocrystals." Journal of the American Chemical Society 128, no. 39 (October 2006): 12598–99. http://dx.doi.org/10.1021/ja0638962.

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30

Wang, Xiaoyong, Xiaofan Ren, Keith Kahen, Megan A. Hahn, Manju Rajeswaran, Sara Maccagnano-Zacher, John Silcox, George E. Cragg, Alexander L. Efros, and Todd D. Krauss. "Non-blinking semiconductor nanocrystals." Nature 459, no. 7247 (May 10, 2009): 686–89. http://dx.doi.org/10.1038/nature08072.

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31

Jana, Santanu, Bhupendra B. Srivastava, Somnath Jana, Riya Bose, and Narayan Pradhan. "Multifunctional Doped Semiconductor Nanocrystals." Journal of Physical Chemistry Letters 3, no. 18 (August 29, 2012): 2535–40. http://dx.doi.org/10.1021/jz3010877.

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32

Biebersdorf, Andreas, Roland Dietmüller, Andrei S. Susha, Andrey L. Rogach, Sergey K. Poznyak, Dmitri V. Talapin, Horst Weller, Thomas A. Klar, and Jochen Feldmann. "Semiconductor Nanocrystals Photosensitize C60Crystals." Nano Letters 6, no. 7 (July 2006): 1559–63. http://dx.doi.org/10.1021/nl060136g.

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33

Jing, Lihong, Stephen V. Kershaw, Yilin Li, Xiaodan Huang, Yingying Li, Andrey L. Rogach, and Mingyuan Gao. "Aqueous Based Semiconductor Nanocrystals." Chemical Reviews 116, no. 18 (September 2, 2016): 10623–730. http://dx.doi.org/10.1021/acs.chemrev.6b00041.

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34

Goldstein, A. N., C. M. Echer, and A. P. Alivisatos. "Melting in Semiconductor Nanocrystals." Science 256, no. 5062 (June 5, 1992): 1425–27. http://dx.doi.org/10.1126/science.256.5062.1425.

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Reiss, Peter, Myriam Protière, and Liang Li. "Core/Shell Semiconductor Nanocrystals." Small 5, no. 2 (January 20, 2009): 154–68. http://dx.doi.org/10.1002/smll.200800841.

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CHAN, YIN THAI. "HETEROSTRUCTURED HYBRID COLLOIDAL SEMICONDUCTOR NANOCRYSTALS." COSMOS 06, no. 02 (December 2010): 235–45. http://dx.doi.org/10.1142/s0219607710000589.

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Significant efforts in the field of colloidal semiconductor particles have been dedicated to the fabrication and study of hybrid metal–semiconductor nanoheterostructures, where the incorporation of the metal moiety may potentially enhance and/or expand existing applications of semiconductor nanoparticles. Many of these metal–semiconductor nanostructured constructs exhibit physical properties not found in either of their metal or semiconductor components, providing many opportunities for further investigation into interface and coupling effects between the two materials. We review some of the key research endeavors in this area, focusing mainly on the synthesis of the materials and the characterization of the various metal–semiconductor constructs, and highlighting some of the unique applications that have emerged from these efforts.

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Zhou, W. L., J. Wiemann, K. L. Stokes, and C. J. O’Connor. "Monodisperse Pbse Nanoparticle Self-Assembling Nanoarrays Before and After Annealing." Microscopy and Microanalysis 7, S2 (August 2001): 314–15. http://dx.doi.org/10.1017/s1431927600027641.

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A variety of semiconductor and metal nanoparticles can be synthesized and tunable in size from about 10 to 200 Å using size-selective separation technique. Preparation of monodisperse samples enables systematic characterization of the structural, electron, and optical properties of materials as they evolve from molecular to bulk in the nanometer size range. Sample uniformity makes it possible to manipulate nanocrystals into close-packed, glassy and ordered nanocrystal. At inter-particle separations 5-100 Å, dipole-dipole interactions lead to energy transfer between neighboring nanocrystals, and electronic tunneling between proximal nanocrystals gives rise to dark and photoconductivity. The fabrication of monodisperse ordered nanoarrays with the inter-particle separations less than 5Å will be very important to study its physical properties since interaction between neighboring nanocrystals cause otherwise insulating assemblies to become semiconducting, metallic, or superconducting depending on nanocrystals composition. Here we present the fabrication of monodisperse PbSe nanoarrays with inter-particle distance less than 5 Å and its nanostructure study.

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Wang, Ying. "Luminescent CdTe and CdSe Semiconductor Nanocrystals: Preparation, Optical Properties and Applications." Journal of Nanoscience and Nanotechnology 8, no. 3 (March 1, 2008): 1068–91. http://dx.doi.org/10.1166/jnn.2008.18156.

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The novel optical and electrical properties of luminescent semiconductor nanocrystals are appealing for ultrasensitive multiplexing and multicolor applications in a variety of fields, such as biotechnology, nanoscale electronics, and opto-electronics. Luminescent CdSe and CdTe nanocrystals are archetypes for this dynamic research area and have gained interest from diverse research communities. In this review, we first describe the advances in preparation of size- and shape-controlled CdSe and CdTe semiconductor nanocrystals with the organometallic approach. This article gives particular focus to water soluble nanocrystals due to the increasing interest of using semiconductor nanocrystals for biological applications. Post-synthetic methods to obtain water solubility, the direct synthesis routes in aqueous medium, and the strategies to improve the photoluminescence efficiency in both organic and aqueous phase are discussed. The shape evolution in aqueous medium via self-organization of preformed nanoparticles is a versatile and powerful method for production of nanocrystals with different geometries, and some recent advances in this field are presented with a qualitative discussion on the mechanism. Some examples of CdSe and CdTe nanocrystals that have been applied successfully to problems in biosensing and bioimaging are introduced, which may profoundly impact biological and biomedical research. Finally we present the research on the use of luminescent semiconductor nanocrystals for construction of light emitting diodes, solar cells, and chemical sensors, which demonstrate that they are promising building blocks for next generation electronics.

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Koslovsky, O., S. Yochelis, N. Livneh, M. G. Harats, R. Rapaport, and Y. Paltiel. "Simple Method for Surface Selective Adsorption of Semiconductor Nanocrystals with Nanometric Resolution." Journal of Nanomaterials 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/938495.

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Self-assembly methods play a major role in many modern fabrication techniques for various nanotechnology applications. In this paper we demonstrate two alternatives for self-assembled patterning within the nanoscale resolution of optically active semiconductor nanocrystals. The first is substrate selective and uses any high resolution surface patterning to achieve localized self-assembly. The second method uses a surface with poly(methyl methacrylate) (PMMA) resist patterning adsorption of the nanocrystal with covalent bonds and liftoff.

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Zhang, Feng, Tianye Zhou, Guogang Liu, Jianbing Shi, Haizheng Zhong, and Yuping Dong. "Tetraphenylethylene derivative capped CH3NH3PbBr3 nanocrystals: AIE-activated assembly into superstructures." Faraday Discussions 196 (2017): 91–99. http://dx.doi.org/10.1039/c6fd00167j.

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The surfaces of semiconductor nanocrystals have been known to be a very important factor in determining their optical properties. The introduction of functionalized ligands can further enhance the interactions between nanocrystals, which is beneficial for the assembly of nanocrystals. In a previous report, we developed a ligand-assisted reprecipitation method to fabricate organometal halide perovskite nanocrystals capped with octylamine and oleic acid. Here, a TPE derivative 3-(4-(1,2,2-triphenylvinyl)phenoxy)propan-1-amine, which shows a typical aggregation induced emission feature, is applied to replace octylamine to fabricate CH₃NH₃PbBr₃ nanocrystals. The obtained CH₃NH₃PbBr₃ nanocrystals were nanocubes (average diameter ∼ 11.1 nm) and are likely to assemble into ordered superstructures. By adjusting the chain length of the TPE derivative, we found that the assembly of the CH₃NH₃PbBr₃ nanocrystals was correlated with the interactions between the TPE groups. This provides a new platform to investigate the ligand effects in nanocrystal solids and may potentially achieve enhanced optical and electrical properties.

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Shi, Frank G. "Size dependent thermal vibrations and melting in nanocrystals." Journal of Materials Research 9, no. 5 (May 1994): 1307–14. http://dx.doi.org/10.1557/jmr.1994.1307.

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A simple model for the size-dependent amplitude of the atomic thermal vibrations of a nanocrystal is presented which leads to the development of a model for the size dependent melting temperature in nanocrystals on the basis of Lindemann's criterion. The two models are in terms of a directly measurable parameter for the corresponding bulk crystal, i.e., the ratio between the amplitude of thermal vibrations for surface atoms and that for interior ones. It is shown that the present model for the melting temperature offers not only a qualitative but even an excellent quantitative agreement with the experimentally observed size-dependent superheating, as well as melting point suppression in both the supported and embedded metallic and semiconductor nanocrystals.

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Moroz, Pavel, Luis Royo Romero, and Mikhail Zamkov. "Colloidal semiconductor nanocrystals in energy transfer reactions." Chemical Communications 55, no. 21 (2019): 3033–48. http://dx.doi.org/10.1039/c9cc00162j.

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Excitonic energy transfer is a versatile mechanism by which colloidal semiconductor nanocrystals can interact with a variety of nanoscale species. This feature article will discuss the latest research on the key scenarios under which semiconductor nanocrystals can engage in energy transfer with other nanoparticles, organic fluorophores, and plasmonic nanostructures, highlighting potential technological benefits to be gained from such processes.

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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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Shih, Yu-Tai, Yu-Ching Tsai, and Der-Yu Lin. "Synthesis and Characterization of CuIn1−xGaxSe2 Semiconductor Nanocrystals." Nanomaterials 10, no. 10 (October 19, 2020): 2066. http://dx.doi.org/10.3390/nano10102066.

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In this paper, the synthesis and characterization of CuIn1−xGaxSe2 (0 ≤ x ≤ 1) nanocrystals are reported with the influences of x value on the structural, morphological, and optical properties of the nanocrystals. The X-ray diffraction (XRD) results showed that the nanocrystals were of chalcopyrite structure with particle size in the range of 11.5–17.4 nm. Their lattice constants decreased with increasing Ga content. Thus, the x value of the CuIn1−xGaxSe2 nanocrystals was estimated by Vegard’s law. Transmission electron microscopy (TEM) analysis revealed that the average particle size of the nanocrystals agreed with the results of XRD. Well-defined lattice fringes were shown in the TEM images. An analysis of the absorption spectra indicated that the band gap energy of these CuIn1−xGaxSe2 nanocrystals was tuned from 1.11 to 1.72 eV by varying the x value from 0 to 1. The Raman spectra indicated that the A1 optical vibrational mode of the nanocrystals gradually shifted to higher wavenumber with increasing x value. A simple theoretical equation for the A1 mode frequency was proposed. The plot of this equation showed the same trend as the experimental data.

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Qiao, Fen. "Semiconductor Nanocrystals for Photovoltaic Devices." Materials Science Forum 852 (April 2016): 935–38. http://dx.doi.org/10.4028/www.scientific.net/msf.852.935.

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Recently, photovoltaic devices based on colloidal semiconductor nanocrystals (NCs) have attracted a great interest due to their flexible synthesis with tunable band gaps and shape-dependent optical and electronic properties. However, the surface of NCs typically presents long chain with electrically insulating organic ligands, which hinder the device applications for NCs. So the major challenge of NCs for photovoltaic devices application is to decrease the inter NC space and the height of the tunnel barriers among NCs, therefore increase the transport properties of NCs. In this article, recent development of colloidal semiconductor NCs and possible routes for improving transport properties of colloidal NCs were reviewed. Among those methods, the thermal annealing approach provides a simple and cost-effective way to fabricate superlattice and to decrease the inter-space among NCs, which may be used for the preparation of other nanocrystalline superstructure and functional devices.

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Feng, Donghai. "Photophysics of Colloidal Semiconductor Nanocrystals." Journal of Physical Chemistry Letters 12, no. 39 (October 7, 2021): 9634–35. http://dx.doi.org/10.1021/acs.jpclett.1c03024.

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Shim, Moonsub, and Philippe Guyot-Sionnest. "n-type colloidal semiconductor nanocrystals." Nature 407, no. 6807 (October 2000): 981–83. http://dx.doi.org/10.1038/35039577.

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Lifshitz, Efrat, and Laurens D. A. Siebbeles. "Fundamental processes in semiconductor nanocrystals." Phys. Chem. Chem. Phys. 16, no. 47 (November 6, 2014): 25677–78. http://dx.doi.org/10.1039/c4cp90174f.

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Guyot-Sionnest, P., and M. A. Hines. "Intraband transitions in semiconductor nanocrystals." Applied Physics Letters 72, no. 6 (February 9, 1998): 686–88. http://dx.doi.org/10.1063/1.120846.

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Lesnyak, V., S. K. Panda, S. G. Hickey, S. Miao, N. Gaponik, and A. Eychmuller. "Emissive Semiconductor Nanocrystals: Recent Progress." ECS Transactions 45, no. 5 (April 27, 2012): 61–66. http://dx.doi.org/10.1149/1.3700410.

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