Search

WO-2026090780-A1 - BLUE-LIGHT QUANTUM DOT MATERIAL, PREPARATION METHOD, AND USE IN OPTOELECTRONIC DEVICE

WO2026090780A1WO 2026090780 A1WO2026090780 A1WO 2026090780A1WO-2026090780-A1

Abstract

Disclosed in the present application are a blue-light quantum dot material, a preparation method, and a use in an optoelectronic device. The quantum dot is composed of a quantum dot core, a first shell layer, and an N-layer outermost shell layer (1≤ N≤ 5). The quantum dot core is composed of binary or higher ZnSeSTe containing Se but not containing Cd, the first shell layer of the quantum dot is composed of ternary or higher CdZnSeS containing Se, and the N-layer outermost shell layer of the quantum dot is composed of binary or higher CdZnSeS. The prepared quantum dot emits light in a pure blue waveband suitable for display applications, having improved spectral properties, light emitting efficiency, and device efficiency compared to the existing technology.

Inventors

  • ZHONG, HAIZHENG
  • WANG, CHENHUI
  • LIU, Mingrui
  • HE, JINHUA

Assignees

  • 北京理工大学

Dates

Publication Date
20260507
Application Date
20241028

Claims (10)

  1. A blue quantum dot material, characterized in that it comprises a quantum dot core, a first shell layer covering the quantum dot core, and N outer shell layers sequentially covering the first shell layer. Where 1≤N≤5; The chemical composition of the quantum dot core is ZnSe x0 Si y0 Te 1-x0-y0 . Where 0 < x 0 ≤ 1, 0 ≤ y 0 < 1, and 0.8 ≤ x 0 + y 0 ≤ 1; The chemical composition of the first shell of the quantum dot is Cd x1 Zn 1-x1 Se y1 S 1-y1 . Where 0 < x1 ≤ 1, 0 < y1 ≤ 1, and x1 and y1 are not both 1 at the same time; The chemical composition of the N-layer outer shell of the quantum dot is independently Cd x2 Zn 1-x2 Se y2 S 1-y2 , Where 0≤x²≤1 , 0≤y²≤1 , and when x² ＝ x¹ , y² ≠ y¹ .
  2. The blue quantum dot material according to claim 1 is characterized in that 0.1≤x 0 ≤1, 0.1≤y 1 ≤1.
  3. The blue quantum dot material according to any one of claims 1-2 is characterized in that the core, the first shell, and the Nth outer shell of the quantum dot are all homogeneous.
  4. The blue quantum dot material according to any one of claims 1-3 is characterized in that the core of the quantum dot contains the element Se, selected from one of ZnSe, ZnSeS, ZnSeTe, and ZnSeSTe.
  5. The blue quantum dot material according to any one of claims 1-4 is characterized in that the first shell of the quantum dot simultaneously contains Cd and Se elements, selected from one of CdZnSe, CdZnSeS, and CdSeS.
  6. The blue quantum dot material according to any one of claims 1-5 is characterized in that the N-layer outermost shell of the quantum dot is independently selected from one of ZnSe, ZnS, CdSe, CdS, CdZnSe, CdZnS, CdSeS, ZnSeS, and CdZnSeS.
  7. The blue quantum dot material according to any one of claims 1-6 is characterized in that the core thickness of the quantum dot is 2-20 nm, the thickness of the first shell layer of the quantum dot is 0.3-10 nm, and the total thickness of the N-layer outermost shell of the quantum dot is 0.3-20 nm.
  8. The blue quantum dot material according to any one of claims 1-7 is characterized in that the center wavelength of the photoexcited fluorescence spectrum of the quantum dot is greater than or equal to 440 nm and less than or equal to 490 nm, and the full width at half maximum (FWHM) of the spectrum is greater than or equal to 8 nm and less than or equal to 40 nm.
  9. The method for preparing the blue quantum dot material according to any one of claims 1 to 8 is characterized by comprising the following steps: S1. Prepare Cd precursor, Zn precursor, Se precursor, S precursor and Te precursor solutions respectively; S2. Preparation of ZnSeSTe nuclear quantum dot solution; S3. Inject Cd precursor, Se precursor, Zn precursor, and S precursor solution into the ZnSeSTe nuclear quantum dot solution obtained in S2. After the reaction, a ZnSeSTe/CdZnSeS quantum dot solution is obtained. S4. Inject Cd precursor, Zn precursor, Se precursor, and S precursor solution into the ZnSeSTe/CdZnSeS quantum dot solution obtained in S3. Perform this operation independently N times to coat the ZnSeSTe/CdZnSeS quantum dots with N layers of CdZnSeS outer shell.
  10. The application of the blue quantum dot material according to any one of claims 1 to 8 in optoelectronic devices, characterized in that the optoelectronic device includes any one of photoluminescent devices, electroluminescent devices, photodetectors, and nonlinear optical devices.

Description

A blue quantum dot material, its preparation method, and its application in optoelectronic devices. Technical Field This application relates to a blue quantum dot material, its preparation method, and its application in optoelectronic devices, belonging to the field of blue quantum dot materials and devices. Background Technology Quantum dots are a novel class of semiconductor nanomaterials, and due to their easily tunable spectra, high fluorescence quantum yield, narrow emission peaks, and solution-processability, they are potential application materials for display technology. Currently, cadmium-based quantum dot materials with core-shell or gradient alloy structures have achieved photoluminescence quantum yields exceeding 80% across the entire display wavelength range (blue, green, and red), and the corresponding external quantum efficiencies of electroluminescent devices have exceeded 20%, approaching the theoretical upper limit. However, the operating lifetime of blue electroluminescent devices lags significantly behind that of red and green devices, and has not yet met the requirements for commercial applications. Using the time T <sub>95</sub> for the device brightness to decay to 95% of its initial brightness of 1,000 nits in constant current mode as an evaluation index for device lifetime, cadmium-based red and green devices have recorded lifetimes of 45,000 hours and 7,200 hours, respectively, while blue devices only reach 227 hours. The quantum dot materials used to display high-efficiency electroluminescence in the blue light (450-480nm) band mainly have CdSe, CdZnSe, CdZnS, CdZnSeS and CdSeS as their cores. Besides the systems mentioned above, quantum dots with InP cores can also achieve blue light emission; however, they have a wide half-width at half-maximum (WHM) (approximately 45 nm) and low efficiency (less than 5%) in electroluminescent devices. Quantum dots with ZnSe cores typically exhibit deep blue light emission (390–445 nm), which does not meet the pure blue light band required for display applications. Quantum dots with tellurium-doped ZnSeTe cores can achieve pure blue light emission and have high fluorescence quantum yield (100%) and high efficiency (over 20%) in electroluminescent devices; however, the resulting emission spectrum broadening (approximately 35 nm) is not conducive to meeting the high color purity required for wide color gamut displays, and the device lifetime has not yet met application requirements. Quantum dots constructed with ZnS cores and CdZnSe or ZnSeTe as quantum wells can also achieve blue light emission; however, the device efficiency and stability are both low. In addition to the shortage of high-performance blue light materials, the environmental problems associated with the heavy metal cadmium are also a major obstacle. One of the major challenges hindering the application of quantum dot displays is the presence of cadmium. The European Union has introduced RoHS (Royal Harmful Materials Directive), which limits the cadmium content to no more than 100 ppm. However, the performance gap between cadmium-free quantum dot materials and devices and cadmium-based materials and devices remains significant. In summary, developing high-efficiency, high-stability, and low-cadmium-content blue light materials and devices is a key challenge for realizing quantum dot full-color display applications. Summary of the Invention The blue quantum dot material provided in this application is a high-efficiency, high-stability, and low-cadmium-content blue light material for electroluminescence. According to the first aspect of this application, a blue quantum dot material is provided. A blue quantum dot material includes a quantum dot core, a first shell layer covering the quantum dot core, and N outer shell layers sequentially covering the first shell layer. Where 1≤N≤5; The chemical composition of the quantum dot core is ZnSe x0 Si y0 Te 1-x0-y0 . Where 0 < x 0 ≤ 1, 0 ≤ y 0 < 1, and 0.8 ≤ x 0 + y 0 ≤ 1; The chemical composition of the first shell of the quantum dot is Cd x1 Zn 1-x1 Se y1 S 1-y1 . Where 0 < x1 ≤ 1, 0 < y1 ≤ 1, and x1 and y1 are not both 1 at the same time; The chemical composition of the N-layer outer shell of the quantum dot is independently Cd x2 Zn 1-x2 Se y2 S 1-y2 , Where 0≤x²≤1 , 0≤y²≤1 , and when x² ＝ x¹ , y² ≠ y¹ . Alternatively, 0.1 ≤ x 0 ≤ 1, 0.1 ≤ y 1 ≤ 1. Optionally, the core, the first shell, and the Nth outer shell of the quantum dot are all homogeneous. Optionally, the core of the quantum dot contains the element Se, selected from one of ZnSe, ZnSeS, ZnSeTe, and ZnSeSTe. Optionally, the first shell of the quantum dot contains both Cd and Se elements, selected from one of CdZnSe, CdZnSeS, and CdSeS. Optionally, the outermost N-layer of the quantum dot is independently selected from one of ZnSe, ZnS, CdSe, CdS, CdZnSe, CdZnS, CdSeS, ZnSeS, and CdZnSeS. Optionally, the core thickness of the quantum dot is 2–20 nm, and the first shell of the quan