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US-12624281-B2 - Light-emitting material, method of preparing the same, and light-emitting device including the light-emitting material

US12624281B2US 12624281 B2US12624281 B2US 12624281B2US-12624281-B2

Abstract

A light-emitting material, including: a quantum dot represented by Formula 1; and Pb(SCN) 2 , wherein a surface of the quantum dot is passivated by the Pb(SCN) 2 , and wherein the light-emitting material has a stretching vibrational peak corresponding to a carbon-nitrogen triple bond in a range of about 2000 inverse centimeter to about 2100 inverse centimeter, as measured by infrared (IR) spectroscopy: A 1 B 1 X 1 3 Formula 1 wherein, in Formula 1, A 1 is at least one of a monovalent organic cation or a monovalent inorganic cation, B 1 is Sn or Pb, and X 1 is at least one halogen.

Inventors

  • Daeyong Son
  • Yongchul Kim

Assignees

  • SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date
20260512
Application Date
20220513
Priority Date
20210514

Claims (19)

  1. 1 . A light-emitting material, comprising: a quantum dot represented by Formula 1; and Pb(SCN) 2 , wherein a surface of the quantum dot is passivated by the Pb(SCN) 2 , and wherein the light-emitting material has a stretching vibrational peak corresponding to a carbon-nitrogen triple bond in a range of about 2000 inverse centimeter to about 2100 inverse centimeter, when measured by infrared (IR) spectroscopy: A 1 B 1 X 1 3 Formula 1 wherein, in Formula 1, A 1 is at least one of a monovalent organic cation or a monovalent inorganic cation, B 1 is Sn or Pb, and X 1 is at least one halogen, wherein the light-emitting material has diffraction peaks corresponding to at least four crystal planes that are a (002) crystal plane, a (100) crystal plane, a (110) crystal plane, a (112) crystal plane, a (200) crystal plane, a (210) crystal plane, a (212) crystal plane, a (220) crystal plane, or a (310) crystal plane, when determined by X-ray diffraction (XRD) analysis.
  2. 2 . The light-emitting material of claim 1 , wherein the quantum dot is represented by Formula 1-A: A 1 PbX 1 3 Formula 1-A wherein, in Formula 1-A, A 1 is at least one of a monovalent organic cation or a monovalent inorganic cation, and X 1 is at least one halogen.
  3. 3 . The light-emitting material of claim 1 , wherein A 1 is Cs + , and X 1 is Cl − , Br − , I − or a combination thereof.
  4. 4 . The light-emitting material of claim 1 , wherein the quantum dot represented by Formula 1 comprises CsPbBr 3 , CsPbBr x Cl (3-x) wherein x is a real number greater than 0 and less than or equal to 3, CsPbCl 3 , or a combination thereof.
  5. 5 . The light-emitting material of claim 1 , wherein the light-emitting material comprises about 0.1 millimoles to about 2 millimoles of Pb(SCN) 2 per 1 millimole of the quantum dot.
  6. 6 . The light-emitting material of claim 1 , wherein the light-emitting material has an absorption peak in a range of about 360 nanometers to about 410 nanometers, when measured by ultraviolet-visible (UV-Vis) absorption spectroscopy.
  7. 7 . The light-emitting material of claim 1 , wherein the light-emitting material has an S 2p peak at a binding energy of about 160 electron volts to about 165 electron volts, when measured by X-ray photoelectron spectroscopy (XPS).
  8. 8 . A light-emitting device, comprising: a first electrode; a second electrode facing the first electrode; and an emission layer located between the first electrode and the second electrode, wherein the emission layer comprises the light-emitting material of claim 1 .
  9. 9 . The light-emitting device of claim 8 , further comprising: a hole transport region located between the first electrode and the emission layer, an electron transport region located between the emission layer and the second electrode, or both a hole transport region located between the first electrode and the emission layer, and an electron transport region located between the emission layer and the second electrode.
  10. 10 . A method of preparing a light-emitting material, the method comprising: disposing a mixture comprising a quantum dot, Pb(SCN) 2 , and a solvent onto a substrate, wherein the quantum dot is represented by Formula 1; and heating the substrate to remove the solvent and form the light-emitting material, wherein a surface of the quantum dot is passivated by the Pb(SCN) 2 : A 1 B 1 X 1 3 Formula 1 wherein, in Formula 1, A 1 is at least one of a monovalent organic cation or a monovalent inorganic cation, B 1 is Sn or Pb, and X 1 is at least one halogen, wherein the light-emitting material has diffraction peaks corresponding to at least four crystal planes that are a (002) crystal plane, a (100) crystal plane, a (110) crystal plane, a (112) crystal plane, a (200) crystal plane, a (210) crystal plane, a (212) crystal plane, a (220) crystal plane, or a (310) crystal plane, when determined by X-ray diffraction (XRD) analysis.
  11. 11 . The method of claim 10 , wherein the mixture comprises about 0.1 millimoles to about 2 millimoles of Pb(SCN) 2 per 1 millimole of the quantum dot.
  12. 12 . The method of claim 10 , wherein the heating of the substrate is performed at 30° C. or higher.
  13. 13 . The method of claim 10 , wherein the solvent is toluene, hexane, benzene, pentane or a combination thereof.
  14. 14 . The method of claim 10 , further comprising, before the step of disposing the mixture, the steps of: forming a first mixed solution by mixing a first precursor solution and a second precursor solution, wherein the first precursor solution comprises a first precursor and a first solvent, and wherein the second precursor solution comprises a second precursor and a second solvent; forming a precipitate by mixing the first mixed solution with a third precursor solution, wherein the third precursor solution comprises a third precursor and a third solvent; separating the precipitate; and dispersing the precipitate in a fourth solvent.
  15. 15 . The method of claim 14 , wherein the precipitate that is dispersed in the fourth solvent comprises a halogen-rich quantum dot; and wherein the first mixed solution comprises a halogen-deficient quantum dot.
  16. 16 . The method of claim 14 , wherein the first precursor is a salt of an ammonium cation, an alkylammonium cation, an arylammonium cation, an arylalkylammonium cation, a formamidinium cation, an alkylamidinium cation, an arylamidinium cation, an arylalkylamidinium cation, or an alkali metal cation, and the second precursor and the third precursor are each independently a salt of a halogen.
  17. 17 . The method of claim 14 , wherein the first solvent, the second solvent, and the third solvent are each independently 1-octadecene (ODE), oleic acid (OA), oleylamine (OLA), or a combination thereof.
  18. 18 . The method of claim 14 , wherein the fourth solvent is diethyl ether, toluene, α-terpineol, hexyl carbitol, ethyl acetate, butyl carbitol acetate, hexyl cellosolve, butyl cellosolve acetate, or a combination thereof.
  19. 19 . The method of claim 14 , further comprising adding a first compound to the precipitate dispersed in the fourth solvent before the step of disposing the mixture.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims priority to Korean Patent Application No. 10-2021-0062945, filed on May 14, 2021 and Korean Patent Application No. 10-2022-0057985, filed on May 11, 2022, in the Korean Intellectual Property Office, and all benefits accruing under 35 U.S.C. § 119, the contents of which are incorporated by reference herein in their entireties. BACKGROUND 1. Field One or more aspects of the present disclosure relate to a light-emitting material, a light-emitting device including the same, and a method of manufacturing the light-emitting material. 2. Description of the Related Art Light-emitting devices are devices that convert electrical energy into light energy. Light-emitting devices commonly include an anode, a cathode, and an emission layer located between the anode and the cathode. Additionally, a hole transport region may be located between the anode and the emission layer, and an electron transport region may be located between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state to thereby generate light. SUMMARY One or more aspects of the present disclosure include a light-emitting material, a light-emitting device including the same, and a method of preparing the light-emitting material. One or more aspects of the present disclosure include a light-emitting material with improved thermal stability and moisture stability, a light-emitting device including the same, and a method of preparing the light-emitting material. Additional aspects will be set forth in part in the detailed description, which follows and, in part, will be apparent from the detailed description, or may be learned by practice of the presented one or more exemplary embodiments of the disclosure. According to an aspect of the present disclosure, provided is a light-emitting material including a quantum dot represented by Formula 1, and Pb(SCN)2, wherein a surface of the quantum dot is passivated by the Pb(SCN)2, and wherein the light-emitting material has a stretching vibrational peak corresponding to a carbon-nitrogen triple bond in a range of about 2000 inverse centimeter (cm−1) to about 2100 cm−1, as measured by infrared (IR) spectroscopy: A1B1X13  Formula 1 wherein, in Formula 1, A1 is at least one of a monovalent organic cation or a monovalent inorganic cation, B1 is Sn or Pb, and X1 is at least one halogen. In one or more embodiments, A1 is at least one of an ammonium cation, an alkylammonium cation, an arylammonium cation, an arylalkylammonium cation, a formamidinium cation, an alkylamidinium cation, an arylamidinium cation, an arylalkylamidinium cation, or an alkali metal cation. In one or more embodiments, A1 may be methylammonium (MA), formamidinium (FA), an alkali metal, or a combination thereof. In one or more embodiments, A1 may be Cs+, and X1 may be Cl−, Br−, I−, or a combination thereof. For example, A1 may be Cs+ and X1 may be Br−. In one or more embodiments, the quantum dot represented by Formula 1 may include CsPbBr3, CsPbBrxCl(3-x) (wherein x is a real number greater than 0 and less than or equal to 3), CsPbCl3, or a combination thereof. For example, the quantum dot represented by Formula 1 may be CsPbBr3. In one or more embodiments, the quantum dot may be halogen-rich, as defined herein. In one or more embodiments, the light emitting material may include about 0.1 millimoles (mmol) to about 2 mmol of Pb(SCN)2 per 1 mmol of the quantum dot. For example, the light emitting material may include about 0.1 mmol to about 1.6 mmol of Pb(SCN)2 per 1 mmol of the quantum dot. For example, the light emitting material may include about 1 mmol or more of Pb(SCN)2 per 1 mmol of the quantum dot. For example, Pb(SCN)2 may be included in a volume ratio of about 100 μl to about 800 μl per 1 mmol of the quantum dot. For example, Pb(SCN)2 may be included in a volume ratio of 390 μl or more per 1 mmol of the quantum dot. In one or more embodiments, the light-emitting material may have an absorption peak present in the range of about 360 nanometer (nm) to about 410 nm in a ultraviolet-visible (UV-Vis) absorption spectrum. In one or more embodiments, the light-emitting material may have an S 2p peak at a binding energy of about 160 electron volts (eV) to about 165 eV, when measured by X-ray photoelectron spectroscopy (XPS). In one or more embodiments, the light-emitting material may have diffraction peaks corresponding to at least four crystal planes that are a (002) crystal plane, a (100) crystal plane, a (110) crystal plane, a (112) crystal plane, a (200) crystal plane, a (210) crystal plane, a (212) crystal plane, a (220) crystal pl