Ionic Crystal Light-Emitting Material for Nanoparticle Stability

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Solution Overview

Problem

Luminescent nanoparticles in existing light-emitting materials are prone to deterioration due to low chemical stability, especially when exposed to water and oxygen, leading to insufficient barrier properties against atmospheric gases.

Innovation Solution

A light-emitting material is developed containing luminescent nanoparticles and an ionic crystal with a specific anionic component, which enhances environmental resistance by reducing hygroscopicity and providing superior barrier properties against gaseous components, using an ionic crystal with a specific anionic component represented by formula (1) that forms a crystalline solid with a high melting point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If luminescent nanoparticles are dispersed in a resin including a constitutional unit derived from an ionic liquid, then the nanoparticles can be stabilized, but the resin has insufficient barrier properties against gaseous components such as oxygen and water vapors, leading to deterioration of luminescent nanoparticles over time

Engineering Contradiction:

Improvestability of luminescent nanoparticlesVSAvoidbarrier properties against oxygen and water vapor

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines luminescent nanoparticles with an ionic crystal having specific hygroscopicity and crystallinity characteristics to create a composite light-emitting material. This composite structure provides both nanoparticle stabilization and superior barrier properties against gaseous components, resolving the contradiction between stability and barrier performance.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If an ionic crystal is used to incorporate luminescent nanoparticles, then the structural stability is improved, but the ionic crystal is hygroscopic and allows water vapor to approach nanoparticles, causing deterioration

Engineering Contradiction:

Improvestructural stability of ionic crystalVSAvoidhygroscopicity and water vapor penetration

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent specifies precise parameter ranges for the ionic crystal: hygroscopicity of 0.5 g/100g or less and crystallinity of 40% or more. By controlling these parameters within specific ranges, the ionic crystal achieves both structural stability and resistance to water vapor penetration, eliminating the harmful hygroscopic effect while maintaining crystal stability.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional ionic crystals are used, then the production process can be simplified, but the luminescent nanoparticles deteriorate due to insufficient barrier properties, requiring complex protective measures

Engineering Contradiction:

Improvesimplicity of production processVSAvoidenvironmental resistance of light-emitting material

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent defines specific parameter ranges for the ionic crystal (hygroscopicity ≤0.5 g/100g, crystallinity ≥40%) that inherently provide superior environmental resistance. This allows the production process to remain simple while achieving high reliability, as the ionic crystal itself provides the necessary protection without requiring additional complex protective layers or processes.

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

The light-emitting material exhibits improved environmental resistance and stability, maintaining emission intensity and spectral purity over time, even in harsh conditions, as demonstrated by relative emission intensity and infrared absorption spectrum tests.

Implementation Method 1

the ionic crystal is hygroscopic, and thus may allow water vapor to approach to the luminescent nanoparticles, causing deterioration of the luminescent nanoparticles

Methodology Applied

Scientific EffectHygroscopicity reduction:

Implementation Method 2

the resin derived from an ionic liquid has insufficient barrier properties against gaseous components such as oxygen and water vapors contained in the air

Methodology Applied

Scientific EffectBarrier properties:

Implementation Method 3

Luminescent nanoparticles are characterized by high luminescent efficiency and narrow spectral half-width, and their luminescent colors are controllable over a wide wavelength region by changing their particle diameters

Methodology Applied

Scientific EffectLuminescence: Luminescence

Data Source

PatentUS11702590B2Light-emitting material and light-emitting device

Publication Date: 2023.07.18 NICHIA CORP

AI summary

A light emitting material includes: luminescent nanoparticles; and an ionic crystal containing an anionic component represented by formula (1) below. In the formula, R1 and R2 each independently denote a fluorine atom or a fluoroalkyl group, or R1 and R2 each denote a fluoroalkylene group to be connected to each other to form a ring.