Quantum dots having composition gradient shell structure and manufacturing method thereof

a technology of composition gradient and quantum dots, which is applied in the direction of luminescent compositions, selenium/tellurium compounds with other elements, and nano-informatics. it can solve the problems of reducing the quantum efficiency of quantum dots, requiring expensive equipment, and difficult to produce large quantities of quantum dots with a uniform size through conventional semiconductor fabrication methods. , to achieve the effect of high luminous efficiency, low cost and short manufacturing tim

US20100140586A1Inactive Publication Date: 2010-06-10SEOUL NAT UNIV R&DB FOUND
4 Cites 87 Cited by

Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
Publication Date
2010-06-10
Estimated Expiration
Not applicable · inactive patent

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

Provided are quantum dots having a gradual composition gradient shell structure which have an improvedluminous efficiency and optical stability, and a method of manufacturing the quantum dots in a short amount of time at low cost. In the method, the quantum dots can be manufactured in a short amount of time at low cost using a reactivity difference between semiconductor precursors, unlike in uneconomical and inefficient conventional methods where shells areformed after forming cores and performing cleaning and redispersion processes. Also, formation of the cores is followed by formation of shells having a composition gradient. Thus, even if the shells are formed to a large thickness, the lattice mismatch between cores and shells is relieved. Furthermore, on the basis of the funneling concept, electrons and holes generated in the shells are transferred to the cores to emit light, thereby obtaining a high luminous efficiency of 80% or more. The quantum dot structure is not limited to Group II-IV semiconductor quantum dots but can be applied to other semiconductors quantum dots, such as Group III-V semiconductors quantum dots and Group IV-IV semiconductors quantum dots. Also, the manufacturing method can be utilized in the development of semiconductor quantum dots having different physical properties, and in various other fields.
Need to check novelty before this filing date? Find Prior Art

Description

TECHNICAL FIELD

[0001] The present invention relates to quantum dots having a gradual composition gradient shell structure and a method of manufacturing the same, and more particularly, quantum dots which have improved luminous efficiency and optical stability owing to a gradual composition gradient shell structure, and a method of manufacturing the same.BACKGROUND ART

[0002] Conventionally, quantum dots have been manufactured using a dry chemical process, specifically, by inducing lattice mismatch between a substrate prepared in a vacuum and a layer deposited using a metal organic chemical vapor deposition (MOCVD) process. In this case, although nanoparticles may be formed and arranged on the substrate, expensive equipments are required. And it is also difficult to produce large quantities of quantum dots with a uniform size through conventional semiconductor fabrication methods. In order to solve these problems, a wet chemical process for synthesizing quantum dots with a uniform size ...

Examples

exemplary embodiment 1

[0042]Synthesis of Quantum Dots with CdSe Cores And ZnS Shells

[0043]FIG. 3 is a diagram illustrating a process of manufacturing quantum dots according to an exemplary embodimentof the present invention, and FIG. 4 is a diagram of experimental equipment used for manufacturing quantum dots according to the present invention. Hereinafter, a process of synthesizing quantum dots with CdSe cores and ZnS shells will be described with reference to FIGS. 3 and 4.

[0044]In step S21, 0.0512 g (0.4 mmol) of solid cadmium oxide (purity: 99.998%), 0.732 g (4 mmol) of zinc acetate, 4.4 ml (17.6 mmol) of oleic acid, and 13.6 ml of 1-octadecene (CH2=CH(CH2)15CH3)were put in a 100 ml round-bottom flask 101 including a syringe 101, a thermometer 104, and a cooler 103. In step S22, the mixture was heated at a pressure of 1 ton and a temperature of about 320° C. for 20 minutes to synthesize a cadmium-oleic acid complex and a zinc-oleic acid complex and remove remaining oxygen from the complexes.

[0045]The...

exemplary embodiment 2

[0048]Synthesis of Quantum Dots with CdSe Cores and ZnSe Shells

[0049]In the present exemplary embodiment, quantum dots were manufactured in the same manner as in the first exemplary embodiment except that 2 ml of 2M trioctylphosphine selenide solution was used instead of the mixtureof trioctylphosphine selenide and trioctylphosphine sulfide used in the first exemplary embodiment.

exemplary embodiment 3

[0050]Synthesis of Quantum Dots with CdTe Cores and ZnS Shells

[0051]In the present exemplary embodiment, quantum dots were manufactured in the same manner as in the first exemplary embodiment except that a 2 ml mixture of 0.2 ml of 2M trioctylphosphine telluridesolution and 1.8 ml of 2M trioctylphosphine sulfide solution was used instead of the mixture of trioctylphosphine selenide and trioctylphosphine sulfide used in the first exemplary embodiment.