InGaP Core/Shell Nanostructures for Blue Light Absorption

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Solution Overview

Problem

There is a need for nanostructure compositions with improved blue light absorbance and low blue light transmittance to enhance the performance of quantum dot color filters and converters in display applications, as existing materials often require additional filters to mitigate blue light leakage, increasing costs and reducing efficiency.

Innovation Solution

The method involves forming In (1-x) Ga x P nanostructures by exchanging organic ligands on InP nanostructures with sulfur-containing inorganic ligands, dissolving them in a molten salt, and alloying gallium to produce nanostructures with enhanced blue light absorption, which are then used in Quantum Dot Enhancement Films (QDEFs) or directly integrated into LED devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional quantum dot materials are used, then the display can be manufactured with standard materials, but blue light leakage occurs requiring additional filters that increase costs and reduce efficiency

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidblue light leakage
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the optical parameters of quantum dots by adjusting their size, composition, and shell structure to enhance blue light absorption. Specifically, the core/shell structure with optimized thickness ratios and material compositions (CdSe, ZnS, MgS) changes the absorption spectrum to strongly absorb blue light wavelengths, eliminating the need for additional filtering layers while maintaining manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite quantum dot structures combining multiple materials (CdSe core, ZnS intermediate shell, MgS outer shell) to achieve superior optical properties. This composite structure enables simultaneous blue light absorption and green light emission with high efficiency, resolving the contradiction between ease of manufacture and blue light leakage control

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If additional filters are introduced to block blue light leakage, then blue light transmittance is reduced, but device complexity and costs increase

Engineering Contradiction:
Improveblue light transmittance controlVSAvoidnumber of filters
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The quantum dot layer serves multiple functions simultaneously: it converts blue LED light to green emission, absorbs excess blue light to prevent leakage, and maintains high overall transmission. This multi-functionality eliminates the need for separate filtering components, reducing device complexity while effectively controlling blue light transmittance

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-generated harmful factors

If quantum dot layer thickness is increased to absorb more blue light, then blue light absorbance improves, but film thickness and down-conversion efficiency are reduced

Engineering Contradiction:
Improveblue light absorbanceVSAvoiddown-conversion efficiency
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The patent creates a core/shell structure with different material compositions and optical properties in different regions. The CdSe core provides strong blue light absorption, while the ZnS and MgS shells provide protective and optical enhancement functions. This local differentiation allows thin film overall thickness while achieving high blue light absorbance and maintaining down-conversion efficiency

Inventive Principle:
Principle #3Local quality

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 approach results in nanostructures that absorb more blue light, reducing the need for additional filters, improving the color gamut and film down-conversion efficiency, and maintaining low blue light transmittance, thereby enhancing the operational efficiency and reducing costs in display technologies.

Implementation Method 1

the wavelength of maximum absorbance for the core/shell nanostructure is between about 430 nm and about 490 nm

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the photoluminescence spectrum for the core/shell nanostructure has an emission maximum between about 500 nm and about 540 nm

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3898887B1Methods for synthesis of inorganic nanostructures using molten salt chemistry
Publication Date: 2024.12.18 SHOEI CHEM IND CO LTD
  • EP3898887B1 patent drawingFigure 1
  • EP3898887B1 patent drawingFigure 2
  • EP3898887B1 patent drawingFigure 3

AI summary

The invention relates to highly luminescent nanostructures with strong blue light absorbance, particularly core/shell nanostructures comprising an In(1-x)GaxP core and ZnSe and/or ZnS shell layers, wherein 0<x<1. The invention also relates to methods of producing such nanostructures.