Perovskite nanocrystal particle light-emitter whose content is changed, method of producing the same, and light emitting element using the same

Patent metadata

Field	Value
Publication number	US-10047284-B2
Application number	US-201515524747-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Nov 6, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

Provided are an organic/inorganic/hybrid perovskite nanocrystal particle light-emitter having a gradient structure, a method of producing the same, and a light emitting element using the same. The organic/inorganic/hybrid perovskite nanocrystal particle light-emitter having a gradient structure includes an organic/inorganic/hybrid perovskite nanocrystal which is dispersible in an organic solvent, wherein the nanocrystal has a gradient composition in which a composition is changed from the center thereof to the outside. Therefore, the gradual change in the content in the nanocrystal may be used to uniformly adjust a fraction in the nanocrystal, to reduce surface oxidation, and to improve exciton confinement in the perovskite present in large quantities inside the nanocrystal, and thus light luminescence efficiency may be improved and durability and stability may be increased.

First claim

The invention claimed is:

1. An organic/inorganic/hybrid perovskite nanocrystal particle light-emitter having a gradient structure, the light-emitter comprising an organic/inorganic/hybrid perovskite nanocrystal structure which is dispersible in an organic solvent or organic material,
wherein the nanocrystal structure has a gradient composition in which a composition is changed from the center thereof to the outside.

2. The light-emitter of claim 1 , wherein the organic solvent includes a polar solvent or a a non-polar solvent,
wherein:
the polar solvent includes dimethylformamide, gamma butyrolactone, N-methylpyrrolidone, dimethyl sulfoxide or isopropyl alcohol; and
the non-polar solvent includes dichloroethylene, trichlorethylene, chloroform, chlorobenzene, dichlorobenzene, styrene, xylene, toluene, or cyclohexene.

3. The light-emitter of claim 1 , wherein the organic/inorganic/hybrid perovskite nanocrystal particle has a spherical, cylindrical, elliptical pillar, polygonal pillar shape.

4. The light-emitter of claim 1 , wherein a size of the nanocrystal particle ranges from 1 nm to 900 nm.

5. The light-emitter of claim 1 , wherein a bandgap energy of the organic/inorganic/hybrid perovskite nanocrystal particle is determined by a crystalline structure without depending on the size of the particle.

6. The light-emitter of claim 1 , wherein the organic/inorganic/hybrid perovskite has a structure of ABX 3-h X′ h , A 2 BX 4-l X′ l , or ABX 4-k X′ k ,
wherein:
A is an organic ammonium material, B is a metal material, X is Br, X′ is Cl, h is real number of 0 to 3, and l and k are real numbers of 0 to 4; and
values of h, l, and k are increased from a center of the nanocrystal structure to the outside.

7. The light-emitter of claim 6 , wherein:
the A is (CH 3 NH 3 ) n , (C m H 2m+1 ) x NH 4-x , ((C m H 2m+1 ) y NH 3-y )(CH 2 ) z NH 3 , (CF 3 NH 3 ), (C m F 2m+1 ) x NH 4-x , ((C m F 2m+1 ) y NH 3-y )(CH 2 ) z NH 3 , (CH(NH 2 ) 2 ), (C m H 2m+1 )(C(NH 2 ) 2 ), (C m F 2m+1 )(C(NH 2 ) 2 ), metal, or a combination thereof (where n, m, x, y, and z are integers greater than 1 or equal to 1); and
the B is a bivalent transition metal, a molecule, a rare-earth metal, an alkaline-earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or a combination thereof.

8. The light-emitter of claim 6 , wherein the values of h, l, and k are gradually increased from the center of the nanocrystal structure to the outside.

9. The light-emitter of claim 6 , wherein the values of h, l, and k are increased stepwise from the center of the nanocrystal structure to the outside.

10. The light-emitter of claim 1 , further comprising a plurality of organic ligands configured to surround the perovskite nanocrystal structure.

11. The light-emitter of claim 10 , wherein the organic ligands include an alkyl halide.

12. The light-emitter of claim 11 , wherein an alkyl structure of the alkyl halide includes an acyclic alkyl having a structure of C n H 2n+1 , a primary alcohol, a secondary alcohol, a tertiary alcohol, an alkylamine, p-substituted aniline, phenyl ammonium, or fluorine ammonium.

13. A light emitting element comprising:
a first electrode;
a second electrode; and
a light emitting layer, which is located between the first electrode and the second electrode and includes the organic/inorganic/hybrid perovskite nanocrystal particle light-emitter having a gradient structure according to claim 1 .

14. A method of producing an organic/inorganic/hybrid perovskite nanocrystal particle light-emitter having a gradient structure, the method comprising:
preparing an organic/inorganic/hybrid perovskite nanocrystal particle having a core-shell structure in which a composition of a core is different from a composition of a shell; and
forming the organic/inorganic/hybrid perovskite nanocrystal particle having a core-shell structure so as to have a gradient composition through interdiffusion by performing heat treatment thereon.

15. The method of claim 14 , wherein the preparing of the organic/inorganic/hybrid perovskite nanocrystal particle having a core-shell structure includes:
preparing a first solution in which a first organic/inorganic/hybrid perovskite is dissolved in a polar solvent and a second solution in which an alkyl halide surfactant is dissolved in an non-polar solvent;
forming a core including a first organic/inorganic/hybrid perovskite nanocrystal by mixing the first solution with the second solution; and
forming a shell, which includes a second organic/inorganic/hybrid perovskite nanocrystal and surrounds the core, by adding a third solution, in which a second organic/inorganic/hybrid perovskite having a larger bandgap than that of the first organic/inorganic/hybrid perovskite is dissolved, to the second solution.

16. The method of claim 15 , wherein:
the first organic/inorganic/hybrid perovskite has a structure of ABX 3 , A 2 BX 4 or ABX 4 ; and
the second organic/inorganic/hybrid perovskite has a structure of ABX′ 3 , A 2 BX′ 4 or ABX′ 4 ,
wherein A is an organic ammonium material, B is a metal material, X is Br, and X′ is Cl.

17. The method of claim 14 , wherein the preparing of the organic/inorganic/hybrid perovskite nanocrystal particle having a core-shell structure includes:
preparing a first solution in which a first organic/inorganic/hybrid perovskite is dissolved in a polar solvent and a second solution in which an alkyl halide surfactant is dissolved in an non-polar solvent;
forming a core including a first organic/inorganic/hybrid perovskite nanocrystal by mixing the first solution with the second solution; and
forming a shell, which has a larger bandgap than that of the core and surrounds the core, by adding an organic ammonium halide solution to the second solution and then stirring.

18. The method of claim 14 , wherein the preparing of the organic/inorganic/hybrid perovskite nanocrystal particle having a core-shell structure includes:
preparing a first solution in which a first organic/inorganic/hybrid perovskite is dissolved in a polar solvent and a second solution in which an alkyl halide surfactant is dissolved in an non-polar solvent;
forming a core including a first organic/inorganic/hybrid perovskite nanocrystal by mixing the first solution with the second solution;
thermally decomposing a surface of the core by performing heat treatment on the second solution; and
forming a shell, which has a larger bandgap than that of the core and surrounds the core, by adding an organic ammonium halide solution to the heat-treated second solution.

19. A method of producing an organic/inorganic/hybrid perovskite nanocrystal particle light-emitter having a gradient structure, the method comprising:
preparing a first solution in which a first organic/inorganic/hybrid perovskite is dissolved in a polar solvent and a second solution in which an alkyl halide surfactant is dissolved in an non-polar solvent;
forming a core including a first organic/inorganic/hybrid perovskite nanocrystal by mixing the first solution with the second solution; and
forming a shell, which has a larger bandgap than that of the core and surrounds the core, by adding a third solution, in which a second organic/inorganic/hybrid perovskite is dissolved, to the second solution while changing a composition of the second organic/inorganic/hybrid perovskite.

20. The method of claim 19 , wherein the second organic/inorganic/hybrid perovskite has a structure of ABX 3-h X′ h , A 2 BX 4-l X′ l , or ABX 4-k X′ k ,
wherein:
A is an organic ammoni

Assignees

• Postech Acad Ind Found

Inventors

• Lee Taewoo
• Im Sanghyuk
• Kim Younghoon
• Cho Himchan

Classifications

• Y02E10/549

  Organic PV cells · CPC title

• C09K11/06 Primary

  containing organic luminescent materials · CPC title

• C09K2211/188

  of other metals not provided for in one of the previous groups · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• H01G9/2059

  comprising an organic dye as the active light absorbing material, e.g. adsorbed on an electrode or dissolved in solution · CPC title