Abstract:
Tin nanoparticles and compositions derived therefrom can be used in a number of different applications. Methods for making tin nanoparticles can include combining a tin (II) salt and a metal salt in a solvent, the metal salt being soluble in the solvent and reducible by the tin (II) salt; reducing the metal salt with a first portion of the tin (II) salt to produce a tin (IV) salt and insoluble nanoparticle seeds formed from the metal salt; and reacting the tin (IV) salt, a second portion of the tin (II) salt, or any combination thereof with a reducing agent to form tin nanoparticles having a nucleus formed from a nanoparticle seed.
Abstract:
Photovoltaic cells having copper contacts can be made by using copper nanoparticles during their fabrication. Such photovoltaic cells can include a copper-based current collector located on a semiconductor substrate having an n-doped region and a p-doped region. The semiconductor substrate is configured for receipt of electromagnetic radiation and generation of an electrical current therefrom. The copper-based current collector includes an electrically conductive diffusion barrier disposed on the semiconductor substrate and a copper contact disposed on the electrically conductive diffusion barrier. The copper contact is formed from copper nanoparticles that have been at least partially fused together. The electrically conductive diffusion barrier limits the passage of copper therethrough.
Abstract:
High-power electronic components generate significant amounts of heat that must be removed in the course of normal device operations. Certain types of electronic components, such as some monolithic microwave integrated circuits and LEDs, can contain materials that are difficult to effectively bond to a heat gink in order to establish a thermal interface between the two. Device assemblies can include a heat-generating electronic component in thermal communication with a metallic heat sink via a metallic thermal interface layer. The metallic thermal interface layer is disposed between the heat-generating electronic component and the metallic heat sink. The metallic thermal interface layer is formed from a composition including a plurality of metal nanoparticles that are at least partially fused together with one another. Methods for forming a thermal interface layer include heating metal nanoparticles above their fusion temperature and subsequently cooling the liquefied metal nanoparticles to promote bonding of the electronic component.
Abstract:
Metal nanoparticles and compositions derived therefrom can be used in a number of different applications. Methods for making metal nanoparticles can include providing a first metal salt in a solvent; converting the first metal salt into an insoluble compound that constitutes a plurality of nanoparticle seeds; and after forming the plurality of nanoparticle seeds, reacting a reducing agent with at least a portion of a second metal salt in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles. Each metal nanoparticle can include a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell can include a metal from the second metal salt. The methods can be readily scaled to produce bulk quantities of metal nanoparticles.
Abstract:
Nanoparticle paste formulations can be configured to maintain a fluid state, promote dispensation, and mitigate crack formation during nanoparticle fusion. Such nanoparticle paste formulations can contain an organic matrix and a plurality of metal nanoparticles dispersed in the organic matrix, where the plurality of metal nanoparticles constitute about 30% to about 90% of the nanoparticle paste formulation by weight. The nanoparticle paste formulations can maintain a fluid state and be dispensable through a micron-size aperture. The organic matrix can contain one or more organic solvents, such as the combination of one or more hydrocarbons, one or more alcohols, one or more amines, and one or more organic acids. Optionally, the nanoparticle paste formulations can contain about 0.01 to about 15 percent by weight micron-scale metal particles or other additives.
Abstract:
An ink adapted for forming conductive elements is disclosed. The ink includes a plurality of nanoparticles and a carrier. The nanoparticles comprise copper and have a diameter of less than 20 nanometers. Each nanoparticle has at least a partial coating of a surfactant configured to separate adjacent nanoparticles. Methods of creating circuit elements from copper-containing nanoparticles by spraying, tracing, stamping, burnishing, or heating are disclosed.
Abstract:
Articles containing a matrix material and plurality of copper nanoparticles in the matrix material that have been at least partially fused together are described. The copper nanoparticles are less than about 20 nm in size. Copper nanoparticles of this size become fused together at temperatures and pressures that are much lower than that of bulk copper. In general, the fusion temperatures decrease with increasing applied pressure and lowering of the size of the copper nanoparticles. The size of the copper nanoparticles can be varied by adjusting reaction conditions including, for example, surfactant systems, addition rates, and temperatures. Copper nanoparticles that have been at least partially fused together can form a thermally conductive percolation pathway in the matrix material.
Abstract:
An ink adapted for forming conductive elements is disclosed. The ink includes a plurality of nanoparticles and a carrier. The nanoparticles comprise copper and have a diameter of less than 20 nanometers. Each nanoparticle has at least a partial coating of a surfactant configured to separate adjacent nanoparticles. Methods of creating circuit elements from copper-containing nanoparticles by spraying, tracing, stamping, burnishing, or heating are disclosed.
Abstract:
A method of fabricating copper nanoparticles includes heating a copper salt solution that includes a copper salt, an N,N'-dialkylethylenediamine, and a C6-C18 alkylamine in an organic solvent to a temperature between about 30°C to about 50°C; heating a reducing agent solution that includes a reducing agent, an N,N'-dialkylethylenediamine, and a C6-C18 alkylamine in an organic solvent to a temperature between about 30°C to about 50°C; and adding the heated copper salt solution to the heated reducing agent solution, thereby producing copper nanoparticles. A composition includes copper nanoparticles, a C6-C18 alkylamine and an N,N'-dialkylethylenediamine ligand. Such copper nanoparticles in this composition have a fusion temperature between about 100°C to about 200°C. A surfactant system for the stabilizing copper nanoparticles includes an N,N'-dialkylethylenediamine and a C6-C18 alkylamine.