Methods for manufacturing spinel-type ternary metal oxides as hole transport materials

Patent metadata

Field	Value
Publication number	US-11820668-B2
Application number	US-201917057119-A
Country	US
Kind code	B2
Filing date	Jul 18, 2019
Priority date	Jul 23, 2018
Publication date	Nov 21, 2023
Grant date	Nov 21, 2023

Abstract

Methods for preparation of surfactant-free ultra-small spinel ternary metal oxide nanoparticles are provided. A method comprises dissolving first and second metal salts in deionized water in a specific mole ratio to form a solution comprising two different metal ions, applying a coprecipitation method and adding an alkaline solution to the solution to form a colloidal suspension, wherein a colloid of the colloidal suspension is a metal hydroxide, adjusting the amount and the addition rate of the alkaline solution to form a specific structure of metal hydroxide precipitate; washing and drying the metal hydroxide to form a structured metal hydroxide powder, and applying a calcination method to the structured metal hydroxide powder to form a surfactant-free spinel-type (AB 2 O 4 ) ternary metal oxide, wherein A and B each respectively comprise a metal element.

First claim

What is claimed is:

1. A method of preparing a surfactant-free spinel-type (AB 2 O 4 ) ternary metal oxide, the method comprising:
dissolving first and second metal salts in deionized water in a specific molar ratio to form a solution comprising two different metal ions;
applying a coprecipitation method and adding an alkaline solution to the solution comprising two different metal ions to form a colloidal suspension,
wherein a colloid of the colloidal suspension is a metal hydroxide;
adjusting the amount and the addition rate of the alkaline solution to form a specific structure of metal hydroxide precipitate;
washing and drying the metal hydroxide precipitate to form a structured metal hydroxide powder; and
applying a calcination method to the structured metal hydroxide powder to form a surfactant-free spinel-type (AB 2 O 4 ) ternary metal oxide,
wherein A and B each respectively comprise a metal element.

2. The method of claim 1 , wherein a particle of the metal hydroxide in the suspension has a diameter of less than 10 nm.

3. The method of claim 1 , wherein the surfactant-free spinel-type (AB 2 O 4 ) ternary metal oxide has crystal structure with an atomic ratio of A:B:O that is 1:2:4.

4. The method of claim 1 , wherein metal element A is nickel, zinc, cobalt, or iron; and wherein metal element B is gallium, iron, chromium, or cobalt.

5. The method of claim 1 , wherein the metal hydroxide is a mixture of a metal hydroxide A(OH) x and a metal hydroxide B(OH) y , or a hydroxide compound of AB x (OH) y , wherein each x and y are a respective stoichiometric number.

6. The method of claim 5 , wherein the hydroxide compound comprises a crystal structure containing metal element A and metal element B, wherein metal element A and metal element B interact with each other, or both metal element A and metal element B interact with a same species.

7. The method of claim 6 , wherein metal element A and metal element B interact through a chemical bond, a coordinate bond, or a mixture thereof.

8. The method of claim 1 , wherein the alkaline solution contains one or more solute selected from the group consisting of NaOH, KOH, NH 4 OH, Na 2 CO 3 , NaHCO 3 , K 2 CO 3 , KHCO 3 , (NH 4 ) 2 CO 3 , NH 4 HCO 3 , CH 3 COONa, and CH 3 COOK.

9. The method of claim 1 , wherein the specific structure of the metal hydroxide comprises a nanoplate, a nanoplate with a wrinkle, a nanoflower, or a mixture thereof.

10. The method of claim 1 , wherein the structured metal hydroxide powder has a formula of A(OH) x (C − ) y (H 2 O)z, B(OH) x (C − ) y (H 2 O)z, or AB n (OH − ) x (C − ) y (H 2 O) z , wherein OH − is a hydroxide ion, C − is a anion from the metal salts or the alkaline solution, and n, x, y, and z are each a respective stoichiometric number.

11. The method of claim 1 , wherein drying the metal hydroxide precipitate comprises thermal drying, vacuum drying, or natural drying.

12. The method of claim 1 , wherein the surfactant-free spinel-type (AB 2 O 4 ) ternary metal oxide is a composite comprising AB 2 O 4 and another species selected from AO, B 2 O 3 , a metal oxide hydroxide BOOH, and an intercalated AB 2 O 4 .

13. The method of claim 12 , wherein the intercalated AB 2 O 4 is in a form of (A 1-x B x )B 2 O 4 , wherein B x is a reduced metal ion with valence of 2 + , and wherein x is a stoichiometric number.

14. The method of claim 1 , wherein the calcination of the structured metal hydroxide powder comprises a solvothermal method, thermal calcination under an ambient condition, or calcination under a reactive atmosphere comprising nitrogen, argon, and hydrogen.

15. The method of claim 14 , wherein the solvothermal method comprises using a solvent selected from water, ethanol, methanol, isopropanol, butanol, benzyl alcohol, ethylene glycol, glycerin, and any mixture thereof.

16. The method of claim 1 , further comprising:
forming a ternary oxide solution by dispersing the surfactant-free spinel-type (AB 2 O 4 ) ternary metal oxide into a solvent; and
forming a ternary metal oxide-based film by processing the ternary oxide solution.

17. The method of claim 16 , wherein the solvent is selected from deionized water, methanol, ethanol, propanol, butanol, chlorobenzene, dichlorobenzene, and any mixture thereof.

18. The method of claim 16 , wherein processing the ternary oxide solution comprises using one or more of a casting technique, a spin-coating technique, a doctor blading technique, a screen printing technique, an ink jet printing technique, a pad printing technique, and a roll-to-roll technique.

19. An optoelectronic device, comprising:
a ternary metal oxide-based film formed according to claim 16 ,
wherein the ternary metal oxide-based film is a carrier transport layer or an electrode of an optoelectronic device.

20. The optoelectronic device of claim 19 , wherein the optoelectronic device is selected from a solar cell, a phototransistor, a photomultiplier, a photoresistor, a light-emitting diode, a laser diodes, a photocatalytic electrode, and a sensor.

Assignees

• Univ Hong Kong

Inventors

• Choy Chik Ho Wallace
• Huang Zhanfeng
• Ou Yangdan

Classifications

• H10K85/50

  Organic perovskites; Hybrid organic-inorganic perovskites [HOIP], e.g. CH3NH3PbI3 · CPC title

• H10K30/50

  Photovoltaic [PV] devices · CPC title

• C01G51/40 Primary

  Complex oxides containing cobalt and at least one other metal element · CPC title

• H10F77/211 Primary

  for photovoltaic cells · CPC title

• H10H20/822

  Materials of the light-emitting regions · CPC title