University of Arkansas

University of California

Xiaogang Peng

David Battaglia

Y Andrew Wang

Jianqing Li

Yunjun Wang

Narayan Pradhan

Armand Paul Alivisatos

Liberato Manna

Lianhua Qu

Nikhil R Jana

Arun Narayanaswamy

Haiyan Chen

Zuoyan Peng

Yongfen Chen

Renguo Xie

Zheng Li

Wenzhou Guo

Lin Song Li

Weiyong Yu

The present invention provides new compositions containing nearly monodisperse colloidal core/shell semiconductor nanocrystals with high photoluminescence quantum yields (PL QY), as well as other complex structured semiconductor nanocrystals. This invention also provides new synthetic methods for preparing these nanocrystals, and new devices comprising these compositions. In addition to core/shell semiconductor nanocrystals, this patent application also provides complex semiconductor nanostructures, quantum shells, quantum wells, doped nanocrystals, and other multiple-shelled semiconductor nanocrystals.

Monodisperse core/shell and other complex structured nanocrystals and methods of preparing the same

Doped semiconductor nanocrystals and methods of making the same are provided.

Metal doped semiconductor nanocrystals and methods of making the same

A nanocrystal described herein comprises a semiconductor material MX, wherein M is a group II or a group III element and X is a group V or a group VI element to provide a II/VI compound or a III/V compound, the nanocrystal having lateral dimensions and a vertical dimension having the shortest axis, wherein surfaces of the nanocrystal normal or substantially normal to the axis of the vertical dimension comprise a layer of M ions passivated by a counter ion chemical species.

Colloidal semiconductor nanocrystals having 1-dimensional quantum confinement and methods of making the same

A method of synthesizing doped semiconductor nanocrystals. In one embodiment, the method includes the steps of combining a metal oxide or metal salt precursor, a ligand, and a solvent to form a metal complex in a reaction vessel; admixing an anionic precursor with the metal complex at a first temperature, T, sufficient to form a plurality of host nanocrystals; doping a metal dopant onto the plurality of the host nanocrystals at a second temperature, T, such that a layer of the metal dopant is formed substantially over the surface of a host nanocrystal that receives a metal dopant; and adding a mixture having the anionic precursor and the metal oxide or metal salt precursor at a third temperature, T, into the reaction vessel to allow regrowth of host nanocrystals on the surface of the layer of the metal dopant formed substantially over the surface of a host nanocrystal that receives a metal dopant to form a plurality of doped nanocrystals, wherein the doped nanocrystals show a characteristic of semiconductor.

Doped semiconductor nanocrystals and methods of making same

A method of synthesizing nanostructures. In one embodiment, the method includes the step of heating a reaction mixture at an elevated temperature, T, for a period of time effective to allow the growth of desired nanostructures. The reaction mixture contains an amount, P, of a carboxylate salt and an amount, L, of a fatty acid ligand, defining a molar ratio of the fatty acid ligand to the carboxylate salt, &#x3b1;=L/P, and a hydrocarbon solvent. The reaction mixture is characterizable with a critical ligand protection, &#x3bc;, associating with the chemical structure of the carboxylate salt such that when &#x3b1;&#x3c;&#x3bc;, the reaction mixture is in a limited ligand protection (LLP) domain, and when &#x3b1;&#x3e;&#x3bc;, the reaction mixture is in a sufficient ligand protection (SLP) domain. The nanostructures are formed in the form of single crystalline and nearly monodisperse nanocrystals, which are in the form of dot-shaped nanocrystals, when the reaction mixture is in the SLP domain, and in the form of nanoflowers, when the reaction mixture is in the LLP domain, respectively.

Multi-dimensional complex nanocrystal structures and methods of making same

A general, reproducible, and simple synthetic method that employs readily available chemicals permits control of the size, shape, and size distribution of metal oxide nanocrystals. The synthesis entails reacting a metal fatty acid salt, the corresponding fatty acid, and a hydrocarbon solvent, with the reaction product being pyrolyzed to the metal oxide. Nearly monodisperse oxide nanocrystals of FeO, CrO, MnO, CoO, NiO, ZnO, SnO, and InO, in a large size range (3-50 nm), are described. Size and shape control of the nanocrystals is achieved by varying the reactivity and concentration of the precursors.

Synthetic control of metal oxide nanocrystal sizes and shapes

Dendron ligands or other branched ligands with cross-linkable groups were coordinated to colloidal inorganic nanoparticles, including nanocrystals, and substantially globally cross-linked through different strategies, such as ring-closing metathesis (RCM), dendrimer-bridging methods, and the like. This global cross-linking reaction sealed each nanocrystal within a dendron box to yield box-nanocrystals which showed dramatically enhanced stability against chemical, photochemical and thermal treatments in comparison to the non-cross-linked dendron-nanocrystals. Empty dendron boxes possessing a very narrow size distribution were formed by the dissolution of the inorganic nanocrystals contained therein upon acid or other etching treatments.

Nanocrystals in ligand boxes exhibiting enhanced chemical, photochemical, and thermal stability, and methods of making the same

Nanoparticle compositions of noble metals, and methods of making them, are described. The nanoparticle compositions are made by reacting a salt or complex of a noble metal, such as Au, Ag, Cu or Pt, with a weak ligand, and a reducing agent, in a single liquid phase. The noble metal is typically provided as a halide or carboxylate. The ligand is preferably a fatty acid or aliphatic amine. The reducing agent is preferably a borohydride reagent, hydrazine, or a mixture thereof. Nanocrystals in the size range of 1 nm to 20 nm are produced, and can be made in substantially monodisperse form.

Monodisperse noble metal nanocrystals

A method for stabilizing colloidal suspensions of nanocrystals or nanoparticles in a solvent or solid matrix is provided by coating the nanocrystals with bulky organic molecules, specifically dendrons. By coating nanocrystals with a dense organic dendron coat and further cross-linking the dendron ligands, oxidation of the nanocrystals and dissociation of the ligands are avoided. This invention allows nanocrystals to undergo rigorous purification and processing. It may regularly be applied to a variety of nanocrystals.

Synthesis of stable colloidal nanocrystals using organic dendrons

The present invention provides substantially monodisperse colloidal nanocrystals and new preparative methods for the synthesis of substantially monodisperse colloidal nanocrystals. These synthetic methods afford the ability to tune nanocrystal size and size distribution. By using non-coordinating solvents in the synthetic process, these procedures constitute easier, less expensive, safer, and more environmentally 'green' methods than those currently in use. This invention is generally applicable to any II&#x2013;VI or III&#x2013;V semiconductor material, and may be useful in generating metal-nonmetal compounds involving transition metals as well.

Growing community of inventors

Fayetteville, AR, United States of America

Xiaogang Peng