Mn4+ Fluoride Phosphor Stabilization for Robust Dispersion

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Solution Overview

Problem

There is a need for improved stability and dispersibility of complex fluoride phosphors used in lighting and display applications, while maintaining their excellent performance.

Innovation Solution

A process for producing a stabilized Mn4+ doped phosphor in solid form involves combining a solution containing substances like K2HPO4, aluminum phosphate, or oxalic acid with a Mn4+ doped phosphor of a specific formula, followed by isolation of the stabilized phosphor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional solid state phosphors are used, then device stability and lifetime are improved, but color mixing and down-conversion losses occur reducing efficiency

Engineering Contradiction:

Improvedevice stability and lifetimeVSAvoiddown-conversion losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the physical state parameter of phosphors from solid to liquid nanodroplets, enabling direct wavelength conversion without the down-conversion losses inherent in conventional solid state phosphors while maintaining device stability through encapsulation in polymer matrices

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If organic liquid phosphors are used, then efficiency is improved, but thermal stability and lifetime are reduced

Engineering Contradiction:

Improveconversion efficiencyVSAvoidthermal stability and lifetime

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent embeds liquid phosphor nanodroplets within polymer matrix capsules, creating a nested structure where the inner liquid phosphor provides high conversion efficiency while the outer polymer shell provides thermal stability and extends device lifetime

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention creates a composite material system combining liquid phosphor nanodroplets with thermally stable polymer matrices, achieving both high conversion efficiency from the liquid phosphor and thermal stability from the polymer encapsulation

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If phosphors are applied to LED chips, then light conversion is achieved, but phosphor settling and hot spots reduce uniformity

Engineering Contradiction:

Improvelight conversionVSAvoidcolor uniformity

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent uses flexible polymer capsules to encapsulate phosphor nanodroplets, creating a conformal coating that adheres to LED chip surfaces and prevents phosphor settling, ensuring uniform light conversion and color distribution without hot spots

Inventive Principle:

Principle #30Flexible shells and thin films

4Reliability

If inorganic phosphors are used, then stability is improved, but synthesis complexity and cost increase

Engineering Contradiction:

ImprovestabilityVSAvoidsynthesis complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs simple, inexpensive organic liquid phosphors that can be readily synthesized or purchased, replacing complex and costly inorganic phosphors while achieving comparable or superior performance through the liquid nanodroplet encapsulation approach

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 process enhances the stability and dispersibility of the phosphors, leading to improved performance in lighting and display applications, with maintained or enhanced quantum efficiency and color stability.

Implementation Method 1

liquid phosphors have shown promise for their direct wavelength conversion capability without the down-conversion losses inherent in conventional solid state phosphors

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

encapsulated in polymer matrices to enhance stability and prevent aggregation

Methodology Applied

Scientific EffectEncapsulation:

Data Source

PatentEP3973034B1Method to enhance phosphor robustness and dispersability and resulting phosphors

Publication Date: 2025.06.04 GE INTELLECTUAL PROPERTY LICENSING LLC

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AI summary

Briefly, in one aspect, the present invention relates to processes for producing a stabilizedMn4+ doped phosphor in solid form and a composition containing such doped phosphor. Such process may include combining a) a solution comprising at least one substance selected from the group consisting of: K2HPO4, an aluminum phosphate, oxalic acid, phosphoric acid, a surfactant, a chelating agent, or a combination thereof, with b) a Mn4+ doped phosphor of formula I in solid form, where formula I may be: Ax [MFy]:Mn4+. The process can further include isolating the stabilizedMn4+ doped phosphor in solid form. In formula I, A may be Li, Na, K, Rb, Cs, or a combination thereof. In formula I, M may be Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof. In formula I, x is the absolute value of the charge of the [MFy] ion and y is 5, 6 or 7.