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Conjugation of DNA to Silanized Colloidal Semiconductor Nanocrystalline Quantum Dots

Description: Water-soluble, highly fluorescent, silanized semiconductor nanocrystals with different surface charges were synthesized. To covalently attach the nanocrystals to biological macromolecules with a variety of mild coupling chemistries, the outermost siloxane shells were derivatized with thiol, amino, or carboxyl functional groups. Single- or double-stranded DNA was coupled to the nanocrystal surfaces by using commercially available bifunctional cross-linker. Conjugation had little effect on the op… more
Date: September 10, 2001
Creator: Parak, Wolfgang J.; Gerion, Daniele; Zanchet, Daniela; Waerz, Anke S.; Micheel, Christine; Williams, Shara C. et al.
Partner: UNT Libraries Government Documents Department
open access

Sorting fluorescent nanocrystals with DNA

Description: Semiconductor nanocrystals with narrow and tunable fluorescence are covalently linked to oligonucleotides. These biocompounds retain the properties of both nanocrystals and DNA. Therefore, different sequences of DNA can be coded with nanocrystals and still preserve their ability to hybridize to their complements. We report the case where four different sequences of DNA are linked to four nanocrystal samples having different colors of emission in the range of 530-640 nm. When the DNA-nanocrystal… more
Date: December 10, 2001
Creator: Gerion, Daniele; Parak, Wolfgang J.; Williams, Shara C.; Zanchet, Daniela; Micheel, Christine M. & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

Semiconductor nanorod liquid crystals

Description: Rodlike molecules form liquid crystalline phases with orientational order and positional disorder. The great majority of materials in which liquid crystalline phases have been observed are comprised of organic molecules or polymers, even though there has been continuing and growing interest in inorganic liquid crystals. Recent advances in the control of the sizes and shapes of inorganic nanocrystals allow for the formation of a broad class of new inorganic liquid crystals. Here we show the form… more
Date: January 28, 2002
Creator: Li, Liang-shi; Walda, Joost; Manna, Liberato & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

Charge transport in hybrid nanorod-polymer composite photovoltaiccells

Description: Charge transport in composites of inorganic nanorods and aconjugated polymer is investigated using a photovoltaic device structure.We show that the current-voltage (I-V) curves in the dark can be modelledusing the Shockley equation modified to include series and shuntresistance at low current levels, and using an improved model thatincorporates both the Shockley equation and the presence of a spacecharge limited region at high currents. Under illumination, theefficiency of photocurrent generati… more
Date: June 21, 2002
Creator: Huynh, Wendy U.; Dittmer, Janke J.; Teclemariam, Nerayo; Milliron, Delia; Alivisatos, A. Paul & Barnham, Keith W.J.
Partner: UNT Libraries Government Documents Department
open access

Formation of hollow nanocrystals through the nanoscale kirkendall effect

Description: We demonstrate that hollow nanocrystals can be synthesized through a mechanism analogous to the Kirkendall Effect, in which pores form due to the difference in diffusion rates between two components in a diffusion couple. Cobalt nanocrystals are chosen as a primary example to show that their reaction in solution with oxygen, sulfur or selenium leads to the formation of hollow nanocrystals of the resulting oxide and chalcogenides. This process provides a general route to the synthesis of hollow … more
Date: March 11, 2004
Creator: Yin, Yadong; Rioux, Robert M.; Erdonmez, Can K.; Hughes, Steven; Somorjai, Gabor A. & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

Preparation of Asymmetric Nanostructures through Site SelectiveModification of Tetrapods

Description: CdTe tetrapods have been deposited on a substrate and partially coated with a protective polymer layer, exposing just one arm. The exposed arm was then decorated with Au nanoparticles in a site selective fashion. The modified arms were readily broken off from the remainder of the tetrapods and released from the substrate, yielding CdTe nanorods asymmetrically modified with Au nanoparticles. These nanostructures with reduced symmetry may show interesting optoelectronic properties.
Date: September 9, 2004
Creator: Liu, Haitao & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

Directed assembly of discrete gold nanoparticle groupings usingbranched DNA scaffolds

Description: The concept of self-assembled dendrimers is explored for the creation of discrete nanoparticle assemblies. Hybridization of branched DNA trimers and nanoparticle-DNA conjugates results in the synthesis of nanoparticle trimer and tetramer complexes. Multiple tetramer architectures are investigated, utilizing Au-DNA conjugates with varying secondary structural motifs. Hybridization products are analyzed by gel electrophoresis, and discrete bands are observed corresponding to structures with incre… more
Date: September 14, 2004
Creator: Claridge, Shelley A.; Goh, Sarah L.; Frechet, Jean M.J.; Williams, Shara C.; Micheel, Christine M. & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

Colloidal nanocrystal synthesis and the organic-inorganicinterface

Description: Colloidal nanocrystals are nanometer-sized, solution-grown inorganic particles stabilized by a layer of surfactants attached to their surface. The inorganic cores exhibit useful properties controlled by composition as well as size and shape, while the surfactant coating ensures that these structures are easy to fabricate and process. It is this combination of features that makes colloidal nanocrystals attractive and promising building blocks for advanced materials and devices. But their full po… more
Date: May 12, 2005
Creator: Yin, Yadong & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

A molecular ruler based on plasmon coupling of single gold andsilver nanoparticles

Description: Molecular rulers based on Foerster Resonance Energy Transfer (FRET) that report conformational changes and intramolecular distances of single biomolecules have helped to understand important biological processes. However, these rulers suffer from low and fluctuating signal intensities from single dyes and limited observation time due to photobleaching. The plasmon resonance in noble metal particles has been suggested as an alternative probe to overcome the limitations of organic fluorophores an… more
Date: May 22, 2005
Creator: Sonnichsen, Carsten; Reinhard, Bjorn M.; Liphardt, Jan & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

Electrical Transport Through a Single Nanoscale SemiconductorBranch Point

Description: Semiconductor tetrapods are three dimensional branched nanostructures, representing a new class of materials for electrical conduction. We employ the single electron transistor approach to investigate how charge carriers migrate through single nanoscale branch points of tetrapods. We find that carriers can delocalize across the branches or localize and hop between arms depending on their coupling strength. In addition, we demonstrate a new single-electron transistor operation scheme enabled by … more
Date: June 9, 2005
Creator: Cui, Yi; Banin, Uri; Bjork, Mikael T. & Alivisatos, A. Paul
Partner: UNT Libraries Government Documents Department
open access

High-Temperature Microfluidic Synthesis of CdSe Nanocrystals inNanoliter Droplets

Description: The high-temperature synthesis of CdSe nanocrystals innanoliter-volume droplets flowing in a perfluorinated carrier fluidthrough a microfabricated reactor is presented. A flow-focusing nanojetstructure with a step increase in channel height reproducibly generatedoctadecene droplets in Fomblin Y 06/6 perfluorinated polyether atcapillary numbers up to 0.81 and with a droplet:carrier fluid viscosityratio of 0.035. Cadmium and selenium precursors flowing in octadecenedroplets through a high-tempera… more
Date: June 9, 2005
Creator: Chan, Emory M.; Alivisatos, A. Paul & Mathies, Richard A.
Partner: UNT Libraries Government Documents Department
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