Embedded Core-Shell Luminescent Material for Chemical Stability

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Solution Overview

Problem

Core-shell semiconductor nanoparticles have a high surface area to volume ratio, leading to low chemical stability and easy deterioration due to exposure to water, oxygen, and other environmental factors.

Innovation Solution

A luminescent material comprising core-shell semiconductor nanoparticles embedded in a metal compound, where the core contains elements such as silver, indium, and sulfur, and the shell is composed of semiconductors like aluminum, gallium, and sulfur, with the metal compound containing zinc and sulfur or oxygen, enhancing the durability of the material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If core-shell semiconductor nanoparticles are used as luminescent material, then emission efficiency and color rendering are improved, but chemical stability deteriorates due to high surface area to volume ratio

Engineering Contradiction:
Improveemission efficiencyVSAvoidchemical stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent embeds core-shell semiconductor nanoparticles within a metal compound matrix, creating a nested structure where the nanoparticles are contained within the larger metal compound. This nested arrangement protects the nanoparticles from environmental factors while maintaining their luminescent properties, thereby improving chemical stability without sacrificing emission efficiency

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent creates a composite material system combining core-shell semiconductor nanoparticles with metal compound (containing Zn, Ga, S, O). This composite structure leverages the luminescent properties of the semiconductor nanoparticles while the metal compound provides chemical stability and protection, resolving the contradiction between emission efficiency and chemical stability

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If core-shell semiconductor nanoparticles are used, then emission spectrum narrowness is improved, but durability worsens due to easy deterioration by water and oxygen

Engineering Contradiction:
Improveemission spectrum narrownessVSAvoiddurability
Core Design Contradiction:
Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The metal compound forms a protective shell or matrix around the core-shell semiconductor nanoparticles. This protective layer acts as a barrier against water and oxygen, preventing deterioration and extending the durability of the luminescent material while preserving the narrow emission spectrum characteristics

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The metal compound creates an inert or protected environment around the semiconductor nanoparticles, isolating them from reactive environmental factors such as water and oxygen. This protective environment maintains both the narrow emission spectrum and enhances durability by preventing oxidation and degradation

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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

The embedding of core-shell semiconductor nanoparticles in a metal compound significantly improves the durability of the luminescent material, reducing deterioration caused by environmental factors and maintaining emission characteristics over time.

Implementation Method 1

core-shell semiconductor nanoparticles that contain first semiconductor nanoparticles and a deposit arranged on surfaces of the cores, and that emit light when irradiated with light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP4119497B1Light emitting material and method for manufacturing same
Publication Date: 2025.04.02 NICHIA CORP
  • EP4119497B1 patent drawingFigure 1
  • EP4119497B1 patent drawingFigure 2
  • EP4119497B1 patent drawingFigure 3

AI summary

Provided is a luminescent material having excellent durability. The luminescent material contains second semiconductor nanoparticles that contain first semiconductor nanoparticles and a deposit arranged on surfaces of the first semiconductor nanoparticles, and that emit light when irradiated with light; and a metal compound in which the second semiconductor nanoparticles are embedded. The first semiconductor nanoparticles contain M1, M2, and Z. M1 is at least one selected from the group consisting of Ag, Cu, Au and alkali metals, and contains at least Ag. M2 is at least one selected from the group consisting of Al, Ga, In and Tl, and contains at least one of In and Ga. Z contains at least one selected from the group consisting of S, Se, and Te. The deposit is substantially composed of at least one selected from the group consisting of Al, Ga, In, Tl and alkali metals, and at least one selected from the group consisting of S, O, Se, and Te. The metal compound contains at least one of Zn and Ga, and at least one of S and O.