# US 9,751,071 B2 · Continuous microwave-assisted segmented flow reactor for high-quality nanocrystal synthesis

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- Number: US 9,751,071 B2
- Document ID: US9751071B2
- Status: Granted
- Kind: B2
- Application number: 14/582,514
- Filed: 2014-12-24
- Published: 2015-07-02
- Granted: 2017-09-05
- Earliest claimed: 2013-12-27
- Assignees: State of Oregon acting by and through the State Board of Higher Education on behalf of Oregon State University
- Applicants: State of Oregon acting by and through the State board of higher education on behalf of OSU
- Inventors: Ki-Joong Kim; Eric Bradley Hostetler; Gregory Scott Herman; Daniel Alan Peterson; Chih-hung Chang; Brendan Thomas Flynn; Brian Kevin Paul; Richard Paul Oleksak
- Web page: https://patentgrep.com/patent/US9751071B2

## CPC

- B01J 19/126: {Microwaves}
- C01B 19/002: {Compounds containing, besides selenium or tellurium, more than one other element, with -O- and -OH not being considered as anions}
- C01B 19/007: {Tellurides or selenides of metals (C01B19/002 takes precedence)}
- C01G 9/08: Sulfides
- C01G 15/006: {Compounds containing gallium, indium or thallium, with or without oxygen or hydrogen, and containing two or more other elements}
- C01G 19/006: {Compounds containing tin, with or without oxygen or hydrogen, and containing two or more other elements}
- C07F 15/045: {without a metal-carbon linkage}
- B01J 2219/0871: Heating or cooling of the reactor
- B01J 2219/0877: Liquid
- C01P 2002/01: depicted by a TEM-image
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2002/78: by stacking-plane distances or stacking sequences
- C01P 2002/80: defined by measured data other than those specified in group C01P2002/70
- C01P 2002/82: by IR- or Raman-data
- C01P 2002/84: by UV- or VIS- data
- C01P 2004/04: obtained by TEM, STEM, STM or AFM
- C01P 2004/51: Particles with a specific particle size distribution
- C01P 2004/64: Nanometer sized, i.e. from 1-100 nanometer
- C01P 2004/80: Particles consisting of a mixture of two or more inorganic phases
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

Systems and methods for synthesizing high-quality nanocrystals via segmented, continuous flow microwave-assisted reactor were developed.

## Claims

### Claim 1

A continuous, microwave-assisted, segmented flow reactor system for nanocrystal synthesis, comprising:
a. a nanocrystal precursor source configured to comprise a nanocrystal precursor solution;
b. a microwave reactor in fluid communication with the nanocrystal precursor source and having a fluid passageway passing through the microwave reactor configured to allow the nanocrystal precursor solution to pass therethrough; and
c. a segmentation fluid source disposed in fluid communication with the fluid passageway at a location between the nanocrystal precursor source and the microwave reactor, the segmentation fluid source configured to provide a segmentation fluid that is immiscible with the nanocrystal precursor solution.

### Claim 2 (depends on 1)

The system of claim 1, wherein the segmentation fluid source comprises a valve.

### Claim 3 (depends on 1)

The system of claim 1, wherein the segmentation fluid source comprises a pump.

### Claim 4 (depends on 1)

The system of claim 1, wherein the segmentation fluid comprises a gas, a liquid, or a combination thereof.

### Claim 5 (depends on 1)

The system of claim 1, wherein the segmentation fluid comprises a gas, a liquid, or a combination thereof where bubble or droplet flow occurs.

### Claim 6 (depends on 1)

The system of claim 1, wherein the nanocrystal precursor solution comprises Cu, In, S, Ga, Se, Pb, Sn, Zn, P, Cd, Te, Ge, Si, Hg, O, Ag, Sb, Bi, Na, or a combination thereof.

### Claim 7 (depends on 1)

The system of claim 1, wherein the nanocrystal precursor source comprises a first nanocrystal precursor source and second nanocrystal precursor source; and the nanocrystal precursor solution comprises a first nanocrystal precursor solution and a second nanocrystal precursor solution.

### Claim 8 (depends on 7)

The system of claim 7, comprising a nanocrystal precursor mixer in fluid communication with the first nanocrystal precursor source and the second nanocrystal precursor source and configured to mix the first nanocrystal precursor solution and the second nanocrystal precursor solution.

### Claim 9 (depends on 7)

The system of claim 7, wherein the first nanocrystal precursor source comprises a first precursor pump and the second nanocrystal precursor source comprises a second precursor pump.

### Claim 10 (depends on 1)

The system of claim 1, comprising a growth chamber for growing nanocrystals in fluid communication with the microwave reactor.

### Claim 11 (depends on 1)

The system of claim 1, wherein the segmentation fluid comprises an inert gas.

### Claim 12

A method for synthesizing nanocrystals using a continuous, microwave-assisted, segmented flow reactor, the method comprising the steps of:
a. providing a nanocrystal precursor solution;
b. segmenting the nanocrystal precursor solution with a segmentation fluid that is immiscible with the nanocrystal precursor solution to yield a segmented nanocrystal precursor solution;
c. continuously flowing the segmented nanocrystal precursor solution through a microwave reactor having a microwave zone; and
d. irradiating the segmented nanocrystal precursor solution flowing through the microwave zone to provide nanocrystals.

### Claim 13 (depends on 12)

The method of claim 12, wherein the step of providing a nanocrystal precursor solution comprises mixing.

### Claim 14 (depends on 12)

The method of claim 12, wherein the segmentation fluid comprises a gas, liquid, or a combination thereof.

### Claim 15 (depends on 12)

The method of claim 12, wherein the step of irradiating comprises a microwave zone residence time of about 0.1 to 100 seconds.

### Claim 16 (depends on 12)

The method of claim 12, wherein the step of irradiating comprises a microwave zone residence time of about 0.1 to 10 seconds.

### Claim 17 (depends on 12)

The method of claim 12, wherein the microwave zone residence time is about 5 seconds.

### Claim 18 (depends on 12)

The method of claim 12, wherein the microwave zone comprises a temperature of about 25 to 250° C.

### Claim 19 (depends on 12)

The method of claim 12, wherein the microwave zone comprises a temperature of about 50 to 200° C.

### Claim 20 (depends on 12)

The method of claim 12, wherein the microwave zone comprises a temperature of about 180° C.

### Claim 21 (depends on 12)

The method of claim 12, further comprising the step of growing nanocrystals in a growth zone.

### Claim 22 (depends on 21)

The method of claim 21, wherein in the step of growing nanocrystals comprises a growth zone residence time of about 5 minutes to 30 minutes.

### Claim 23 (depends on 22)

The method of claim 22, wherein the growth zone residence time is about 20 minutes.

### Claim 24 (depends on 21)

The method of claim 21, wherein the growth zone comprises a temperature of about 50 to 250° C.

### Claim 25 (depends on 21)

The method of claim 21, wherein the growth zone comprises a temperature of about 210° C.

### Claim 26 (depends on 12)

The method of claim 12, wherein the nanocrystal precursor solution comprises Cu, In, S, Ga, Se, Pb, Sn, Zn, P, Cd, Te, Ge, Si, Hg, O, Ag, Sb, Bi, Na, or a combination thereof.

### Claim 27 (depends on 12)

The method of claim 12, wherein the nanocrystal precursor solution comprises Cu, In, Se, Pb, S, Sn, Zn, or a combination thereof.

### Claim 28 (depends on 12)

The method of claim 12, wherein the nanocrystal precursor solution comprises Cu, In, Se, or a combination thereof.

### Claim 29 (depends on 12)

The method of claim 12, wherein the nanocrystal comprises CuInSe2, PbSe, CuInS2, Cu2ZnSnS4, or a combination thereof.

### Claim 30 (depends on 12)

The method of claim 12, wherein the nanocrystal comprises CuInSe2.

### Claim 31 (depends on 12)

The method of claim 12, wherein the nanocrystal precursor solution comprises a first and second nanocrystal precursor.

### Claim 32 (depends on 12)

The method of claim 12, wherein the nanocrystal precursor solution comprises oleylamine, trioctylphosphine, trioctylphosphine oxide, hexadecylamine, water, triethylene glycol, ethylene glycol, oleic acid, dodecanethiol, dioctyl ether, 1-octadecene, glycerol, 1,3-propanediol-1,4-butanediol, or a combination thereof.

### Claim 33 (depends on 12)

The method of claim 12, wherein the segmentation fluid comprises an inert gas.

### Claim 34

A continuous flow reactor comprising:
a mixer for mixing a first and a second precursor together into a mixture and providing the mixture to a fluid passageway;
a segmentation fluid source for inserting a gas into the fluid passageway to provide segmented flow of the mixture along the fluid passageway;
an energy source for nucleating the segmented flow of the mixture in the fluid passageway, thereby producing nucleates; and
a heating source for growing the nucleates in the fluid passageway thereby growing the nucleates into nanoparticles.

### Claim 35 (depends on 34)

The continuous flow reactor of claim 34, wherein the energy source is a microwave.

### Claim 36 (depends on 34)

The continuous flow reactor of claim 34, wherein the gas comprises an inert gas.