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https://www.readbyqxmd.com/read/28719199/giant-pbse-cdse-cdse-quantum-dots-crystal-structure-limited-ultrastable-near-infrared-photoluminescence-from-single-nanocrystals
#1
Christina J Hanson, Nicolai F Hartmann, Ajay Singh, Xuedan Ma, William J I DeBenedetti, Joanna L Casson, John K Grey, Yves J Chabal, Anton V Malko, Milan Sykora, Andrei Piryatinski, Han Htoon, Jennifer A Hollingsworth
Toward a truly photostable PbSe quantum dot (QD) we apply the thick-shell or "giant" QD structural motif to this notoriously environmentally sensitive nanocrystal system. Namely, using a sequential application of two shell-growth techniques-partial-cation exchange and successive ionic layer adsorption and reaction (SILAR)-we are able to overcoat the PbSe QDs with sufficiently thick CdSe shells to impart new single-QD-level photostability as evidenced by suppression of both photobleaching and blinking behavior...
July 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28719145/preparation-of-carbon-dot-based-ratiometric-fluorescent-probes-for-cellular-imaging-from-curcuma-longa
#2
Zihnil Adha Islamy Mazrad, Eun Bi Kang, Insik In, Sung Young Park
This work derived biocompatible and stable probes based on fluorescent nanoparticles (FNPs) from a natural source, Curcuma longa. The multi-color fluorescence emissions from carbonized Curcuma longa (C-FNPs) obtained through defined dehydration conditions are soluble in water and have a small particle size (~17 nm). The surface passivation with polyethylene glycol (PEG) capped with amine groups in FNPs (P-FNPs) generated a probe with a higher quantum yield and longer fluorescence lifetime than obtained with C-FNPs...
July 18, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28719080/near-infrared-quantum-dots-in-biomedical-applications-current-status-and-future-perspective
#3
REVIEW
Peng Zhao, Quan Xu, Jia Tao, Zongwen Jin, Yue Pan, Changmin Yu, Zhiqiang Yu
To address the requirements of biomedical applications including biosensing, bioimaging, and drug delivery, fluorescent nanomaterials served as efficient tools in many cases. Among them, near-infrared quantum dots (NIR QDs) have been used as novel fluorescent labels for their binary advantages of both QDs and NIR light. In this review, through collecting references in recent 10 years, we have introduced basic structures and properties of NIR QDs and summarized the classification and the related synthetic methods...
July 18, 2017: Wiley Interdisciplinary Reviews. Nanomedicine and Nanobiotechnology
https://www.readbyqxmd.com/read/28718918/a-rapid-confirmatory-test-for-body-fluid-identification
#4
Stephanie T Young, Joshua R Moore, Clifton P Bishop
We have developed a technique that allows investigators to confirm the presence of blood, semen, and/or saliva in a crime scene sample. It is a confirmatory test where multiple samples can be processed in less than an hour, and it is potentially portable, permitting samples to be processed at the crime scene. Samples at a scene giving a positive result can be further processed while those failing to do so may be ignored. There is a large and growing backlog of DNA evidence in the USA, slowing down the criminal justice system...
July 18, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28718456/graphene-oxide-and-dna-aptamer-based-sub-nanomolar-potassium-detecting-optical-nanosensor
#5
Debopam Datta, Ketaki Sarkar, Souvik Mukherjee, Xenia Meshik, Michael A Stroscio, Mitra Dutta
Quantum-dot (QD) based nanosensors are frequently used by researchers to detect small molecules, ions and different biomolecules. In this article, we present a sensor complex/system comprised of deoxyribonucleic acid (DNA) aptamer, gold nanoparticle and semiconductor QD, attached to a graphene oxide (GO) flake for detection of potassium. As reported herein, it is demonstrated that QD-aptamer-quencher nanosensor functions even when tethered to GO, opening the way to future applications where sensing can be accomplished simultaneously with other previously demonstrated applications of GO such as serving as a nanocarrier for drug delivery...
July 18, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28718290/enhanced-long-term-and-thermal-stability-of-polymer-solar-cells-in-air-at-high-humidity-with-the-formation-of-unusual-quantum-dot-networks
#6
Long Tan, Fan Yang, Mee Rahn Kim, Pandeng Li, Deepak Thrithamarassery Gangadharan, Joelle Margot, Ricardo Izquierdo, Mohamed Chaker, Dongling Ma
Due to the practical applications of polymer solar cells (PSCs), their stability recently has received increasing attention. Herein, a new strategy was developed to largely enhance the long-term and thermal stability of PSCs in air with a relatively high humidity of 50-60% without any encapsulation. In this strategy, semiconductor PbS/CdS core/shell quantum dots (QDs) were incorporated into the photoactive blend of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM). By replacing the initial ligands of oleic acid with halide ligands on the surface of PbS/CdS QDs via solution-phase-ligand-exchange, we were able to form unusual, continuous QD networks in the film of P3HT:PCBM, which effectively stabilized the photoactive layer...
July 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28717581/detection-of-echinococcus-granulosus-antigen-by-a-quantum-dot-porous-silicon-optical-biosensor
#7
Yanyu Li, Zhenhong Jia, Guodong Lv, Hao Wen, Peng Li, Hongyan Zhang, Jiajia Wang
Highly sensitive labeled detection of Echinococcus granulosus using colloidal quantum dots (QDs) based on a porous silicon Bragg mirror sensor are demonstrated. Rabbit anti-p38 labeled CdSe/ZnS QDs was infiltrated in porous silicon pores immobilized Egp38 antigen. QD-antibodies are specifically bound to antigens linked covalently to the pore walls of PSi after the immune reaction. By the design of the transfer matrix method and the preparation of the electrochemical etching method, the fluorescence peak wavelength of the quantum dots is located in the forbidden band of the Bragg mirror...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28717208/macroscopic-singlet-triplet-qubit-in-synthetic-spin-one-chain-in-semiconductor-nanowires
#8
Blazej Jaworowski, Nick Rogers, Marek Grabowski, Pawel Hawrylak
We show here how to create macroscopic quantum states in a semiconductor device: a chain of InAs quantum dots embedded in an InP nanowire. Filling the nanowire with 4 electrons per dot creates a synthetic spin-one chain, with four-fold degenerate topological ground state protected by a Haldane gap. The four states correspond to two spin-½ quasiparticles localised at the ends of the macroscopic wire. The quasiparticle spins are mapped onto a robust, macroscopic, singlet-triplet qubit. These predictions are supported by a microscopic theory and extensive numerical simulations...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28717126/2d-0d-graphene-hybrids-for-visible-blind-flexible-uv-photodetectors
#9
Hiroyuki Tetsuka
Nitrogen-functionalized graphene quantum dots (NGQDs) are attractive building blocks for optoelectronic devices because of their exceptional tunable optical absorption and fluorescence properties. Here, we developed a high-performance flexible NGQD/graphene field-effect transistor (NGQD@GFET) hybrid ultraviolet (UV) photodetector, using dimethylamine-functionalized GQDs (NMe2-GQDs) with a large bandgap of ca. 3.3 eV. The NMe2-GQD@GFET photodetector exhibits high photoresponsivity and detectivity of ca. 1...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28715636/backbone-engineered-%C3%AE-peptide-amphitropic-gels-for-immobilization-of-semiconductor-quantum-dots-and-2d-cell-culture
#10
Rajkumar Misra, Aman Sharma, Anjali Shiras, Hosahudya N Gopi
We are reporting a spontaneous supramolecular assembly of backbone engineered γ-peptide scaffold and its utility in the immobilization of semiconductor quantum dots and in cell culture. The stimulating feature of this γ-peptide scaffold is that it efficiently gelate both aqueous phosphate buffers as well as aromatic organic solvents. A comparative and systematic investigation reveals that the greater spontaneous self-aggregation property of γ-peptide over the α-, and β-peptide analogues is mainly due to the backbone flexibility, increased hydrophobicity and "π-π stacking of γ-phenylalanine residues...
July 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28714202/an-all-solution-based-hybrid-cmos-like-quantum-dot-carbon-nanotube-inverter
#11
Artem G Shulga, Vladimir Derenskyi, Jorge Mario Salazar-Rios, Dmitry N Dirin, Martin Fritsch, Maksym V Kovalenko, Ullrich Scherf, Maria A Loi
The development of low-cost, flexible electronic devices is subordinated to the advancement in solution-based and low-temperature-processable semiconducting materials, such as colloidal quantum dots (QDs) and single-walled carbon nanotubes (SWCNTs). Here, excellent compatibility of QDs and SWCNTs as a complementary pair of semiconducting materials for fabrication of high-performance complementary metal-oxide-semiconductor (CMOS)-like inverters is demonstrated. The n-type field effect transistors (FETs) based on I(-) capped PbS QDs (Vth = 0...
July 17, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28713845/impact-of-phonons-on-dephasing-of-individual-excitons-in-deterministic-quantum-dot-microlenses
#12
Tomasz Jakubczyk, Valentin Delmonte, Sarah Fischbach, Daniel Wigger, Doris E Reiter, Quentin Mermillod, Peter Schnauber, Arsenty Kaganskiy, Jan-Hindrik Schulze, André Strittmatter, Sven Rodt, Wolfgang Langbein, Tilmann Kuhn, Stephan Reitzenstein, Jacek Kasprzak
Optimized light-matter coupling in semiconductor nanostructures is a key to understand their optical properties and can be enabled by advanced fabrication techniques. Using in situ electron beam lithography combined with a low-temperature cathodoluminescence imaging, we deterministically fabricate microlenses above selected InAs quantum dots (QDs), achieving their efficient coupling to the external light field. This enables performing four-wave mixing microspectroscopy of single QD excitons, revealing the exciton population and coherence dynamics...
December 21, 2016: ACS Photonics
https://www.readbyqxmd.com/read/28711617/highly-sensitive-label-free-immunosensing-of-prostate-specific-antigen-using-poly-cysteine-caped-by-graphene-quantum-and-gold-nanoparticle-a-novel-signal-amplification-strategy
#13
Hediyeh Malekzad, Mohammad Hasanzadeh, Nasrin Shadjou, Abolghasem Jouyban
A mediator-free electrochemical immunosensor for quantitation of prostate specific antigen (PSA) based on dual signal amplification strategy was fabricated. In this work, PSA-antibody (anti-PSA) was immobilized onto a green and biocompatible nanocomposite containing poly L-cysteine (P-Cys) as conductive matrix and graphene quantum dots (GQDs)/gold nanoparticles (GNPs) as dual signal amplification elements. Therefore, a novel multilayer film based on P-Cys, GQDs, and GNPs was exploited to develop a highly sensitive amperometric immunosensor for detection of PSA...
July 12, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28711028/fluorescence-based-cdte-nanosensor-for-sensitive-detection-of-cytochrome-c
#14
Rehab M Amin, Souad A Elfeky, Thomas Verwanger, Barbara Krammer
Cytochrome c (Cyt c) is commonly used as intrinsic biomarker for several characteristics of the cell such as respiration, energy level and apoptosis. In the present study a simple colorimetric sensor should be developed and tested for the real-time detection of Cyt c in living cells. We synthesized cadmium telluride quantum dots (CdTe QDs) capped with thioglycolic acid (TGA) as a fluorometric Cyt c nanosensor. The synthesized TGA/CdTe QDs nanosensor was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and absorption as well as fluorescence spectrophotometry...
July 8, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28710930/immobilization-effects-on-the-photocatalytic-activity-of-cds-quantum-dots-horseradish-peroxidase-hybrid-nanomaterials
#15
Iker Iñarritu, Eduardo Torres, Antonio Topete, José Campos-Terán
The potential use of hybrid nanomaterials based on inorganic optically active nanoparticles known as quantum dots (QDs) and horseradish peroxidase (HRP) has been proposed by several authors as light-controllable nanocatalyzers, moreover, the immobilization within or over silica based supports represents an advantage over bulk-dispersed systems. However, the implications of the immobilization of such hybrid photoactivatable catalyzing systems have not been clarified with detail. Here, we present a thorough study of the functional photoactive efficiency and recycling of immobilized CdS QDs and HRP systems with different configurations, immobilized over silanized silica quartz crystal microbalance (QCM) sensors, allowing an accurate measure of the immobilized mass of each component and its correlation with the initial reaction rate of conversion of Amplex Red (AR) to resorufin...
July 6, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28710929/tunable-emission-of-cu-mn-doped-znins-quantum-dots-via-dopant-interaction
#16
Jiatao Zhu, Shiliang Mei, Wu Yang, Guilin Zhang, Qiuhang Chen, Wanlu Zhang, Ruiqian Guo
In this work, transition metal ion- doped zinc-based quantum dots (QDs) are synthesized via a greener controllable method to avoid the toxicity of the traditional cadmium-based QDs and broaden the tunable emission. Herein, the tunable emission of Cu-doped ZnInS/ZnS core-shell QDs (Cu:ZnInS/ZnS) can cover from 500 to 620nm by varying the Cu dopant concentration from 1 to 20% and the maximum quantum yield can reach 49.8%. Based on the single-doped QDs, Cu,Mn co-doped ZnInS/ZnS core-shell QDs (Cu,Mn:ZnInS/ZnS) with a photoluminance (PL) quantum yield of 30...
June 15, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28710414/resonant-driving-of-a-single-photon-emitter-embedded-in-a-mechanical-oscillator
#17
Mathieu Munsch, Andreas V Kuhlmann, Davide Cadeddu, Jean-Michel Gérard, Julien Claudon, Martino Poggio, Richard J Warburton
Coupling a microscopic mechanical resonator to a nanoscale quantum system enables control of the mechanical resonator via the quantum system and vice-versa. The coupling is usually achieved through functionalization of the mechanical resonator, but this results in additional mass and dissipation channels. An alternative is an intrinsic coupling based on strain. Here we employ a monolithic semiconductor system: the nanoscale quantum system is a semiconductor quantum dot (QD) located inside a nanowire. We demonstrate the resonant optical driving of the QD transition in such a structure...
July 14, 2017: Nature Communications
https://www.readbyqxmd.com/read/28709375/examining-the-roles-of-emulsion-droplet-size-and-surfactant-in-the-interfacial-instability-based-fabrication-process-of-micellar-nanocrystals
#18
Yuxiang Sun, Ling Mei, Ning Han, Xinyi Ding, Caihao Yu, Wenjuan Yang, Gang Ruan
The interfacial instability process is an emerging general method to fabricate nanocrystal-encapsulated micelles (also called micellar nanocrystals) for biological detection, imaging, and therapy. The present work utilized fluorescent semiconductor nanocrystals (quantum dots or QDs) as the model nanocrystals to investigate the interfacial instability-based fabrication process of nanocrystal-encapsulated micelles. Our experimental results suggest intricate and intertwined roles of the emulsion droplet size and the surfactant poly (vinyl alcohol) (PVA) used in the fabrication process of QD-encapsulated poly (styrene-b-ethylene glycol) (PS-PEG) micelles...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28709312/minimal-motor-for-powering-particle-motion-from-spin-imbalance
#19
Ulf Bissbort, Colin Teo, Chu Guo, Giulio Casati, Giuliano Benenti, Dario Poletti
We introduce a minimalistic quantum motor for coupled energy and particle transport. The system is composed of two spins, each coupled to a different bath and to a particle which can move on a ring consisting of three sites. We show that the energy flowing from the baths to the system can be partially converted to perform work against an external driving, even in the presence of moderate dissipation. We also analytically demonstrate the necessity of coupling between the spins. We suggest an experimental realization of our model using trapped ions or quantum dots...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28709143/using-silicon-coated-gold-nanoparticles-to-enhance-the-fluorescence-of-cdte-quantum-dot-and-improve-the-sensing-ability-of-mercury-ii
#20
Jian Zhu, Hui Chang, Jian-Jun Li, Xin Li, Jun-Wu Zhao
The effect of silicon-coated gold nanoparticles with different gold core diameter and silica shell thickness on the fluorescence emission of CdTe quantum dots (QDs) was investigated. For gold nanoparticles with a diameter of 15nm, silica coating can only results in fluorescence recover of the bare gold nanoparticle-induced quenching of QDs. However, when the size of gold nanoparticle is increased to 60nm, fluorescence enhancement of the QDs could be obtained by silica coating. Because of the isolation of the silica shell-reduced quenching effect and local electric field effect, the fluorescence of QDs gets intense firstly and then decreases...
June 30, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
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