2567 results about "Quantum yield" patented technology

A water soluble semiconductor nanocrystal capable of light emission is provided, including a quantum dot having a selected band gap energy, a layer overcoating the quantum dot, the overcoating layer comprised of a material having a band gap energy greater than that of the quantum dot, and an organic outer layer, the organic layer comprising a compound having a least one linking group for attachment of the compound to the overcoating layer and at least one hydrophilic group space apart from the linking group by a hydrophobic region sufficient to prevent electron charge transfer across the hydrophobic region. The particle size of the nanocrystal core is in the range of about 12.ANG. to about 150.ANG., with a deviation of less than 10% in the core. The coated nanocrystal exhibits photoluminescende having quantum yield of greater than 10% in water.

A coated nanocrystal capable of light emission includes a substantially monodisperse nanoparticle selected from the group consisting of CdX, where x=S, Se, Te and an overcoating of ZnY, where Y=S, Se, uniformly deposited thereon, said coated nanoparticle characterized in that when irradiated the particles exhibit photoluminescence in a narrow spectral range of no greater than about 60 nm, and most preferably 40 nm, at full width half max (FWHM). The particle size of the nanocrystallite core is in the range of about 20 Å to about 125 Å, with a deviation of less than 10% in the core. The coated nanocrystal exhibits photoluminescence having quantum yields of greater than 30%.

The present invention provides a fluorescent silica-based nanoparticle that allows for precise detection, characterization, monitoring and treatment of a disease such as cancer The nanoparticle has a fluorescent compound positioned within the nanoparticle, and has greater brightness and fluorescent quantum yield than the free fluorescent compound To facilitate efficient urinary excretion of the nanoparticle, it may be coated with an organic polymer, such as polyethylene glycol) (PEG) The small size of the nanoparticle, the silica base and the organic polymer coating minimizes the toxicity of the nanoparticle when administered in vivo The nanoparticle may further be conjugated to a ligand capable of binding to a cellular component associated with the specific cell type, such as a tumor marker A therapeutic agent may be attached to the nanoparticle Radionuclides/radiometals or paramagnetic ions may be conjugated to the nanoparticle to permit the nanoparticle to be detectable by various imaging techniques.

The invention belongs to the technical field of preparation of a carbon nano material, and particularly relates to a method for preparing a carbon dot having a high fluorescent quantum yield from citric acid and different nitrogen-containing molecules. The method comprises the following steps: weighing 1-10 mmol of solid citric acid, and dissolving in 10 ml of deionized water; weighing 1-10 mmol of ethylenediamine, ethylamine, propylamine, butanediamine, n-hexylamine, p-phenylene diamine or urea, adding into the citric acid solution, and uniformly stirring; transferring the solution into a hydrothermal or high-pressure microwave reaction kettle, reacting under hydrothermal or microwave conditions, and naturally cooling the reaction kettle to room temperature, thus obtaining a yellow or brown carbon dot water solution; and finally, purifying the carbon dot water solution, evaporating, and drying to obtain pure carbon dot solid powder. The carbon dot solution can send out bright blue fluorescence under the irradiation of a handheld ultraviolet lamp. The invention has wide application prospects in the fields of biological imaging, fluorescent printing and the like.

The present invention provides new compositions containing colloidal nanocrystals with high photoluminescence quantum yields, new synthetic methods for the preparation of highly luminescent colloidal nanocrystals, as well as methods to control the photoluminescent properties of colloidal nanocrystals. The new synthetic methods disclosed herein allow photoemission brightness (quantum yield) to be correlated with certain adjustable nanocrystal growth parameters associated with a given synthetic scheme.

The invention relates to a photoactive component, especially a solar cell, comprising organic layers and formed by at least one stacked pi, ni, and/or pin diode. The diodes are characterised in that they comprise at least one p-doped or n-doped transport layer having a larger optical band gap than that of the photoactive layer. The individual diodes are characterised by a high internal quantum yield, but can be optically thin (peak absorption <80%). A high external quantum yield is obtained by either enlarging the optical path of the incident light in the diodes using light traps, or by stacking a plurality of the diodes. The transition between two diodes being facilitated by transition layers for the purposes of improved recombination and generation. Both forms of embodiment have a number of specific advantages using the doped transport layers with a large band gap.

Functionalized fluorescent nanocrystal compositions and methods for making and using these compositions are disclosed. The compositions are fluorescent nanocrystals coated with at least one material. The coating material has chemical compounds or ligands with functional groups or moieties with conjugated electrons and moieties for imparting solubility to coated fluorescent nanocrystals in aqueous solutions. The coating material provides for functionalized fluorescent nanocrystal compositions which are water soluble, chemically stable, and emit light with a high quantum yield and/or luminescence efficiency when excited with light. The coating material may also have chemical compounds or ligands with moieties for bonding to target molecules and cells as well as moieties for cross-linking the coating. In the presence of reagents suitable for reacting to form capping layers, the compounds in the coating may form a capping layer on the fluorescent nanocrystal with the coating compounds operably bonded to the capping layer.

Fluorescent dyes are disclosed which are useful as reporter groups for labeling biomolecules. The silicon phthalocyanine dyes disclosed are preferably water soluble, isomericly pure, possess high quantum yield, and are useful in bioassays.

The present invention provides a fluorescent silica-based nanoparticle that allows for precise detection, characterization, monitoring and treatment of a disease such as cancer. The nanoparticle has a range of diameters including between about 0.1 nm and about 100 nm, between about 0.5 nm and about 50 nm, between about 1 nm and about 25 nm, between about 1 nm and about 15 nm, or between about 1 nm and about 8 nm. The nanoparticle has a fluorescent compound positioned within the nanoparticle, and has greater brightness and fluorescent quantum yield than the free fluorescent compound. The nanoparticle also exhibits high biostability and biocompatibility. To facilitate efficient urinary excretion of the nanoparticle, it may be coated with an organic polymer, such as poly(ethylene glycol) (PEG). The small size of the nanoparticle, the silica base and the organic polymer coating minimizes the toxicity of the nanoparticle when administered in vivo. In order to target a specific cell type, the nanoparticle may further be conjugated to a ligand, which is capable of binding to a cellular component associated with the specific cell type, such as a tumor marker. In one embodiment, a therapeutic agent may be attached to the nanoparticle. To permit the nanoparticle to be detectable by not only optical fluorescence imaging, but also other imaging techniques, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), computerized tomography (CT), bioluminescence imaging, and magnetic resonance imaging (MRI), radionuclides/radiometals or paramagnetic ions may be conjugated to the nanoparticle.

The present invention provides a process for preparing carbon quantum dots having uniform size by using emulsion, and a process for doping the inside of the carbon structure with other element or replacing the surface with a surface stabilizer having a specific chemical functional group different from existing stabilizers in order to control the properties of the carbon quantum dots. The process for preparing the carbon quantum dots according to the present invention makes a mass production possible and the process thereof is simple. Furthermore, the process is easy to control the size of the quantum dots and the reaction yield rate of the method is excellent. In addition, according to the present invention, it is possible to synthesize carbon quantum dots having uniform size and superior quantum yield rate and it makes it possible to embody the color as equivalent to existing molecular chromophores or heavy metal quantum dots by changing the structure of the chromophore.

The invention relates to fluorescent dyes (fluorophores) based on polymethines for use in optical measurement and detection procedures, in particular those employing fluorescence, for example in medicine, in pharmacology and in the biological, materials and environmental sciences. The objective was to create fluorophores based on polymethines that have a large Stokes shift, high photostability, long storage life and a high fluorescent quantum yield, and that can be excited in the simplest possible manner by white-light sources or laser radiation in the UV, visible or NIR spectral region. According to the invention dyes on the basis of polymethines having the general formulas I, II or III are employed.

The invention discloses a liquid crystal display screen, a display device and a quantum dot layer graphical method. A plurality of pixel units are arranged in a liquid crystal panel; each pixel unit comprises a plurality of subpixel units capable of displaying different colors; and a monochromatic quantum dot layer is arranged at the position corresponding to at least one color of subpixel unit of each pixel unit. The embodiment of the invention substitutes the quantum dot layer for the conventional resin to serve as a color filter for converting background light into monochromatic light, the emission spectrum of the quantum dots is narrow and the luminous efficiency is high, and the background light can be efficiently converted into monochromic light, so the color gamut of the liquid crystal display screen can be improved, the color saturation is enhanced and the display quality of the display screen is improved. The monochromic quantum dots are dispersed by a high-molecular polymer network, so accumulation of the quantum dots can be avoided, the quantum yield is increased, the quantum excited lighting effect can be improved, contact of the monochromic quantum dots and oxygen can be avoided, and the service life of the quantum dots is prolonged.

The present invention discloses the preparation process of CdSe/CdS, CdSe/ZnS and other II-VI type core-shell quantum dot. The CdSe/CdS and CdSe/ZnS core-shell quantum dot are prepared with cadmium acetate, zinc acetate or other inorganic compound, instead of Cd(CH3)2, Zn(CH3)2 or other inflammable, detonable and expensive organic metal compound, as material. The prdouct has excellent single dispersivity, improved fluorescent property, high quantum yield, high stability, and may be used widely as the fluorescent mark for biological detection and analysis.

In a GaN-based light-emitting diode structure, a transparent conductive oxide layer is formed as a window layer on a GaN contact layer having a surface textured layer, and the textured layer acts as an ohmic contact layer with the transparent conductive oxide layer. Therefore, it is possible to reduce effectively the contact resistance and the working voltage, while the optical guiding effect is interrupted by the textured layer, to obtain thereby an enhancement of light extraction efficiency and thus an increase in the external quantum yield.

The invention discloses a fluorine-boron fluorescent dye as well as a preparation method and application thereof, wherein the structure of the fluorine-boron fluorescent dye is shown as a formula (I) or a formula (II), in the formula (I) and the formula (II), R1 is H or halogen; R2 is CN; R3, R4, R5 and R6 are independently selected from H, halogen, C1-C6 alkyl or C1-C6 alkoxy; V, W, X, Y and Z are independently CH or N, and when V, W, X, Y or Z is N, N has no substituent group. According to the fluorine-boron fluorescent dye and the preparation method thereof, the maximal fluorescence emission wavelength of the fluorine-boron fluorescent dye is 518-600nm, and the fluorine-boron fluorescent dye also has excellent fluorescence quantum yield and Stokes shift, which shows that the fluorine-boron fluorescent dye has good application prospect in the bioanalysis fields of fluorescence labeling, bioimaging and so on; meanwhile, the preparation method is simple in steps, and raw materials can be obtained easily.

Highly fluorescent carbon nanoparticles (FCNs), with tunable emission colours of particle size between 1-10 nm also stable in solid form with high quantum yield (>5%) and its method of synthesis thereof yielding said carbon nanoparticles in milligram to gram scale in high synthesis yield (>80%). The present invention also provides for highly fluorescent carbon nanoparticle solution doped with heteroatom (such as oxygen, nitrogen) and its method of synthesis favoring yield of the said doped carbon nanoparticles of even smaller size ranging from 1-5 nm with narrow size distribution, and also provides for functionalized FCNs that are non-toxic, functional, soluble and stable fluorescent carbon nanoparticles with retained fluorescence for variety of end uses in biomedics, imaging applications, and detection techniques.

A method and apparatus for illuminating a subject with deep UV light and detecting 2-dimensional image information, e.g., a transmission image, fluorescence image, reflected light image, etc. The subject may be illuminated with a light pulse having a duration of 2 seconds or less and one or more components with a wavelength of between about 150 nm to about 300 nm. The light pulse may be arranged so as to minimize or eliminate any detrimental effect on the functioning of the subject, e.g., on a living cell. A concentration, mass, quantum yield, absorbance or other characteristics of one or more compounds in the subject may be determined based on one or more 2-dimensional images obtained of the subject. An illumination beam having left and right circularly polarized components may be generated, e.g., for circular dichroism analysis of a subject.

The invention discloses an iridium complex phosphor material taking a phthalazine derivative as a ligand. The structure of the material is shown as formulas (I) and (II), wherein Ar represents aryl, substituted aryl, heterocycle aryl and substituted heterocycle aryl; R can be one of a halogen atom, alkyl, substituted alkyl, alkoxyl, aryloxy, an alkylthio group, arylthio, aromatic amino, aliphatic amino or a heterocyclic substituent; L^Y can be one of N-COOH, 8-hydroxyquinoline, beta-diketone, N^NH and the like; N^N can be bipyridyl, diquinoline, 1,10-phenanthroline, a derivative of the 1,10-phenanthroline and the like; and Z can be hexafluorophosphate and perchlorate. A dicyclic or ionic iridium complex phosphorescent electroluminescent device taking the phthalazine derivative as the ligand obtained with the preparation method has high internal and external quantum yields, high luminance and high stability. A dicyclic iridium complex is shown as a formula (I), i.e., (C^N)2Ir(L^Y); and an ionic iridium complex is shown as a formula (II), i.e., (C^N)2Ir(N^N)<+>Z<->.

The invention discloses a preparation method and application of a polyaniline/titanium dioxide/graphene conductive composite membrane. The preparation method comprises the steps of: adding 3-60wt% of titanium dioxide, 0.05-5wt% of graphene and 0.6-10wt% of polyaniline into protonic acid solution, and adopting an in-situ polymerization method to obtain a polyaniline/titanium dioxide/graphene conductive composite; sequentially and evenly coating conductive resin and polyaniline/titanium dioxide/graphene coatings to matrixes such as polypropylene, glass slides, metal plates and the like, wherein each coating is 30-500mu m thick; and drying at 60-80 DEG C to obtain the needed product. According to the preparation method, the titanium dioxide is embedded in a conductive material to prepare the membrane, the defects that the nano TiO2 is not easy to recover and the quantum yield is low can be overcome, the separation efficiency of photoproduction electrons and cavities can be improved, the photoresponse range can be extended, and the photocatalytic efficiency can be improved.