US5637258A
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Method for producing rare earth activited metal oxide nanocrystals
Assignee: Nanocrystals Technology LP
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Filing: 1996-03-18
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Granted: 1997-06-10
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Expires: 2016-03-18
Abstract
Abstract A process for the production of metal oxide nanocrystalline phosphors activated with a rare earth, line emitting, element. The nanocrystal oxides are produced by a sol-gel like process. The process begins with an n-butoxide solution of the host and activator which is first subject to acetolysis which will cause the pH of the solution to change from basic to acidic. This is followed by the addition of water in a hydrolysis step which forms a host/activator hydroxide solution. To the host/activator hydroxide solution, sodium hydroxide, which is very basic, is added, which will cause the precipitation of host oxide nanocrystals activated with the activator. The host/activator n-butoxide precursors may be synthesized by azeotropic distillation.
Inventors
- 👤 Efim T. Goldburt
- 👤 Rameshwar N. Bhargava
- 👤 Bharati S. Kulkarni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:17
CPC Classifications
B; B82; B82Y; B82Y30/00; C; C01; C01B; C01B13/00; C01B13/14; C01B13/32; C01F; C01F17/00; C01F17/20; C01F17/206; C01F17/218; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7701; C09K11/7702; C09K11/7715; C09K11/7716; C09K11/7717; C09K11/7728; C09K11/7729; C09K11/773; C09K11/7743; C09K11/7744; C09K11/7745; C09K11/7756; C09K11/7759; C09K11/776; C09K11/7766; C09K11/7767; C09K11/7783; C09K11/7784; C01P; C01P2002/00; C01P2002/50; C01P2002/52; C01P2004/00; C01P2004/60; C01P2004/64; C01P2006/00; C01P2006/60
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
98 words
A process for producing yttrium oxide host nanocrystals having diameters of less than 100 angstroms, said nanocrystals being activated with a rare earth activator, the process comprising the steps of: a) providing a n-butoxide first solution containing yttrium and the activator in a compatible solvent; b) adding acetic acid to the first solution to form a yttrium-activator acetate; c) adding water to the first solution to hydrolyze the yttrium-activator acetate to form a hydroxide compound of the yttrium and the activator; and d) adding sodium hydroxide to the solution to precipitate yttrium oxide nanocrystals activated with the activator.
Claim 2
Dependent Claim
98 words
A process for producing yttrium oxide host nanocrystals having diameters of less than 100 angstroms, said nanocrystals being activated with a rare earth activator, the process comprising the steps of: a) providing a n-butoxide first solution containing yttrium and the activator in a compatible solvent; b) adding acetic acid to the first solution to form a yttrium-activator acetate; c) adding water to the first solution to hydrolyze the yttrium-activator acetate to form a hydroxide compound of the yttrium and the activator; and d) adding sodium hydroxide to the solution to precipitate yttrium oxide nanocrystals activated with the activator.
Claim 3
Dependent Claim
26 words
The process as claimed in claim 1 wherein the activator is selected from the group consisting of europium, terbium, thulium, cerium, gadolinium, holmium, samarium and neodymium.
Claim 4
Dependent Claim
39 words
The process as claimed in claim 1 wherein the n-butoxide first solution is provided by the mixture of Yttrium n-butoxide and an n-butoxide of the activator, with the n-butoxide of the activator being 5-25% by volume of the mixture.
Claim 5
Dependent Claim
29 words
The process as claimed in claim 1 further including the step of producing the n-butoxide compounds of the host and activator by exchange of iso-propoxide groups for n-butoxide groups.
Claim 6
Dependent Claim
23 words
The process as claimed in claim 4 wherein the step of exchanging the iso-propoxide groups for n-butoxide groups is accomplished by azeotropic distillation.
Claim 7
Dependent Claim
35 words
The process as claimed in claim 4 further including the step of forming the iso-propoxide groups from the reaction of sodium iso-propoxide with a chloride compound containing at least one of the host and activator.
Claim 8
Dependent Claim
23 words
The process as claimed in claim 6 further including the step of forming the sodium iso-propoxide from the reaction of sodium with iso-propanol.
Claim 9
Dependent Claim
12 words
The process as claimed in claim 1 wherein the solvent is n-butanol.
Claim 10
Dependent Claim
94 words
A process for producing host metal oxide nanocrystals having diameters of less than 100 angstroms, said nanocrystals being activated with an activator element, the process comprising the steps of: a) providing a host/activator n-butoxide first solution in a compatible solvent; b) adding acetic acid to the first solution to form a host-activator acetate; c) adding water to the first solution to hydrolyze the host-activator acetate to form a hydroxide compound of the host and the activator; and d) rapidly adding sodium hydroxide to the solution to precipitate host oxide nanocrystals activated with the activator.
Claim 11
Dependent Claim
94 words
A process for producing host metal oxide nanocrystals having diameters of less than 100 angstroms, said nanocrystals being activated with an activator element, the process comprising the steps of: a) providing a host/activator n-butoxide first solution in a compatible solvent; b) adding acetic acid to the first solution to form a host-activator acetate; c) adding water to the first solution to hydrolyze the host-activator acetate to form a hydroxide compound of the host and the activator; and d) rapidly adding sodium hydroxide to the solution to precipitate host oxide nanocrystals activated with the activator.
Claim 12
Dependent Claim
31 words
The process as claimed in claim 9 wherein the activator element is a rare earth element selected from the group consisting of europium, terbium, thulium, cerium, gadolinium, holmium, samarium and neodymium.
Claim 13
Dependent Claim
58 words
The process as claimed in claim 9 wherein the host metal oxide is selected from the group consisting of yttrium oxide, zirconium oxide (ZrO 2 ), zinc oxide (ZnO), gadolinium oxide (Gd 2 O 3 ), praseodymium oxide (Pr 2 O 3 ), lanthanum oxide (La 2 O 3 ), and copper oxide (CuO or Cu 2 O).
Claim 14
Dependent Claim
43 words
The process as claimed in claim 9 wherein the n-butoxide first solution is provided by the mixture of n-butoxide compound of the host and an n-butoxide compound of the activator, with the n-butoxide of the activator being 5-25% by volume of the mixture.
Claim 15
Dependent Claim
30 words
The process as claimed in claim 12 wherein at least one of the n-butoxide compounds of the host and activator is provided by exchange of iso-propoxide groups by n-butoxide groups.
Claim 16
Dependent Claim
22 words
The process as claimed in claim 13 further including the step of exchanging the iso-propoxide groups for n-butoxide groups by azeotropic distillation.
Claim 17
Dependent Claim
35 words
The process as claimed in claim 13 further including the step of forming the iso-propoxide groups from the reaction of sodium iso-propoxide with a chloride compound containing at least one of the host and activator.
Claim 18
Dependent Claim
23 words
The process as claimed in claim 15 further including the step of forming the sodium iso-propoxide from the reaction of sodium with iso-propanol.
Claim 19
Dependent Claim
12 words
The process as claimed in claim 9 wherein the solvent is n-butanol.
Claim 20
Dependent Claim
28 words
The process as claimed in claim 9 wherein the activator element is a transition metal selected from the group consisting of maganese, copper, silver, cobalt, nickel, and iron.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-06-09 | 2000-12-09 | 2001-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-09 | 2004-12-09 | 2005-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-09 | 2008-12-09 | 2009-06-10 | $7700.00 | Window Closed / Lapsed |