Silicon/germanium-based nanoparticle pastes with ultra low metal contamination
OwnerHa Thi-Hoang Nguyen, Masaya Soeda +2inventors
InventorsHa Thi-Hoang Nguyen, Masaya Soeda, Weidong Li, Uma Srinivasan
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Abstract
Silicon based nanoparticle inks are described with very low metal contamination levels. In particular, metal contamination levels can be established in the parts-per-billion range. The inks of particular interest generally comprise a polymer to influence the ink rheology. Techniques are described that are suitable for purifying polymers soluble in polar solvents, such as alcohols, with respect metal contamination. Very low levels of metal contamination for cellulose polymers are described.
Claims30
A nanoparticle ink comprising at least about 0.1 weight percent silicon/germanium-based inorganic nanoparticles and at least about 1 weight percent polymer having a molecular weight of at least 500 daltons, wherein the paste has an iron content of no more than about 100 ppb and wherein the polymer comprises an organic polymer comprising a cellulose-based polymer, a poly(vinyl alcohol), a poly(vinyl ester), polyvinyl amides, a polysiloxane polymer, polyacrylates, polyacrylic acid, polyvinyl butyrl or a combination thereof.
A cellulose polymer having a iron contamination, chromium contamination, copper contamination and nickel contamination individually of no more than about 100 ppb by weight as evaluated in a 7 weight percent solution.
A method for the purification of an organic polymer soluble at a concentration of at least about 0.5 weight percent in ethanol and having a molecular weight of at least 200 amu, the method comprising:
- separating the polymer from an acidified aqueous solution having a pH of no more than about 4 pH units to obtain a polymer with a reduced metal content.
A method for the purification of a polymer soluble at a concentration of at least about 0.5 weight percent in ethanol, the method comprising,
- filtering a dissolved solution of the polymer through an ion removal media to reduce the iron contamination to no more than about 100 ppb as determined in a 7 weight percent polymer solution.
Dependencies are inferred from the claim text.