Core-Shell Quantum Dots Uniform Shell Formation

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Solution Overview

Problem

The luminous efficiency of core-shell semiconductor particles, particularly those with a core-shell structure of Group III-V and Group II-VI semiconductors, is affected by the synthesis process and can be suboptimal due to non-uniform shell formation and insufficient core coverage.

Innovation Solution

The core-shell particles are designed with a core containing a Group III element and a shell formed from a Group II-VI semiconductor, where the peak intensity ratio of the Group II element to the Group III element, as measured by X-ray photoelectron spectroscopy, is 0.25 or higher, and the method involves preparing a mixed solution with Group III and Group II raw materials, forming the core, and then adding a Group VI raw material to form the shell at a temperature of 230°C or higher.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional synthesis processes are used to form core-shell particles, then the shell can be formed around the core, but the shell formation is non-uniform and core coverage is insufficient, leading to reduced luminous efficiency

Engineering Contradiction:
Improveshell formation uniformityVSAvoidluminous efficiency
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the shell formation temperature to 230°C or higher, which fundamentally alters the reaction kinetics and surface chemistry during shell deposition. This temperature parameter change enables uniform shell formation and complete core coverage, directly resolving the contradiction between manufacturing precision and luminous efficiency by creating a synthesis condition where both are simultaneously maximized

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the shell thickness is increased to improve coverage, then core coverage may improve, but the synthesis complexity and process control difficulty increase

Engineering Contradiction:
Improvecore coverageVSAvoidsynthesis process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent simplifies the synthesis process by changing the temperature parameter to 230°C or higher, which enables uniform shell formation at controlled thickness without requiring complex multi-step procedures. This single parameter change achieves both complete core coverage and maintains process simplicity, resolving the contradiction between reliability and device complexity

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the luminous efficiency of the core-shell particles, with improved uniformity of the shell coverage leading to increased signal intensity and enhanced light emission efficiency.

Implementation Method 1

a method for producing core-shell particles, the method including preparing a mixed solution by mixing a Group III raw material including a Group III element with a Group II raw material including a Group II element, and dissolving the raw materials; forming a core containing the Group III element and a Group V element; and adding a Group VI raw material including a Group VI element to the mixed solution after the forming of the core, and forming a shell containing the Group II element and the Group VI element on at least a portion of a surface of the core

Methodology Applied
Scientific EffectChemical Vapor Deposition: Chemical Vapour Deposition

Implementation Method 2

the peak intensity ratio of the Group II element to the Group III element, as measured by X-ray photoelectron spectroscopy, is 0.25 or higher

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS10711190B2Core-shell particles, method for producing core-shell particles, and film
Publication Date: 2020.07.14 FUJIFILM CORP

AI summary

Provided are core-shell particles that have high luminous efficiency and are useful as quantum dots, a method for producing the same, and a film produced using the core-shell particles. The core-shell particles of the invention are core-shell particles having a core containing a Group III element and a Group V element; and a shell covering at least a portion of the surface of the core and containing a Group II element and a Group VI element, in which the proportion of the peak intensity ratio of the Group II element with respect to the peak intensity ratio of the Group III element as measured by X-ray photoelectron spectroscopy analysis is 0.25 or higher.