High yield method for preparing silicon nanocrystals with chemically accessible surfaces
AssigneeEvergreen Solar, Inc.
InventorsSusan M. Kauzlarich, Richard K. Baldwin
Life of this patent
Estimating the term…
Abstract
Silicon nanocrystals with chemically accessible surfaces are produced in solution in high yield. Silicon tetrahalide such as silicon tetrachloride (SiCl4) can be reduced in organic solvents, such as 1,2-dimethoxyethane (glyme), with soluble reducing agents, such as sodium naphthalenide, to give halide-terminated (e.g., chloride-terminated) silicon nanocrystals, which can then be easily functionalized with alkyl lithium, Grignard or other reagents to give easily processed silicon nanocrystals with an air and moisture stable surface. The synthesis can be used to prepare alkyl-terminated nanocrystals at ambient temperature and pressure in high yield. The two-step process allows a wide range of surface functionality.
Claims26
A method for producing silicon nanocrystals comprising the steps of:
- contacting a silicon halide and a first reducing agent in a first organic solvent to produce halide-terminated silicon nanocrystals;
- and
- contacting the halide-terminated silicon nanocrystals and a second reducing agent along with a preselected termination group in a second organic solvent to produce silicon nanocrystals terminated with the preselected termination group,
- wherein at least one of the first and second reducing agents is an elemental metal having an oxidation potential greater than 0.24V and the elemental metal is in finely divided form.
A method for producing silicon nanocrystals comprising the steps of:
- contacting a silicon halide and a first reducing agent in a first organic solvent to produce halide-terminated silicon nanocrystals;
- and
- contacting the halide-terminated silicon nanocrystals and a second reducing agent along with a preselected termination group in a second organic solvent to produce silicon nanocrystals terminated with the preselected termination group,
- wherein at least one of the first and second reducing agents comprises a liquid alloy comprising one metal component that has an oxidation potential greater than 0.24V.
A method for producing silicon nanocrystals comprising the steps of:
- contacting a silicon halide and a first reducing agent in a first organic solvent to produce halide-terminated silicon nanocrystals;
- and
- contacting the halide-terminated silicon nanocrystals and a second reducing agent along with a preselected termination group in a second organic solvent to produce silicon nanocrystals terminated with the preselected termination group,
- wherein at least one of the first and second reducing agents comprises a mixture of an alkali metal and a phase transfer catalyst.
A method for producing silicon nanocrystals comprising the steps of:
- contacting a silicon halide and a first reducing agent in a first organic solvent to produce halide-terminated silicon nanocrystals;
- and
- contacting the halide-terminated silicon nanocrystals and a second reducing agent along with a preselected termination group in a second organic solvent to produce silicon nanocrystals terminated with the preselected termination group,
- wherein the first and second reducing agents are the same.
A method for producing silicon nanocrystals comprising the steps of:
- contacting a silicon halide and a first reducing agent in a first organic solvent to produce halide-terminated silicon nanocrystals;
- and
- contacting the halide-terminated silicon nanocrystals and a second reducing agent along with a preselected termination group in a second organic solvent to produce silicon nanocrystals terminated with the preselected termination group,
- wherein the preselected termination group comprises an alkyl termination group, a hydride termination group, an alkoxy termination group, an amino termination group, or a mixture thereof and is an oligomeric or polymeric group.
Dependencies are inferred from the claim text.