Plasmonic OLED Enhancement Layer for Color Saturation

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Solution Overview

Problem

Conventional OLEDs face challenges in achieving efficient and cost-effective production of saturated colors for full-color displays, particularly in terms of red, green, and blue sub-pixels, due to limitations in material properties and emission mechanisms.

Innovation Solution

The integration of a plasmonic OLED structure with an enhancement layer that includes a plasmonic material for surface plasmon resonance, combined with outcoupling layers and color filters, to enhance light emission and conversion into individual sub-pixel colors, allowing for broadband emission and efficient color rendering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional OLED materials and configurations are used, then device simplicity is maintained, but color saturation and emission efficiency deteriorate

Engineering Contradiction:

Improvecolor saturationVSAvoiddevice structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The OLED device is segmented into multiple functional layers including a hole injection layer, hole transport layer, emissive layer, electron transport layer, and electron injection layer. Each layer is optimized for specific functions to achieve saturated color emission while maintaining manageable complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structures where the emissive layer contains phosphorescent emitters combined with host materials, and transport layers use doped organic compounds. These composite structures enable enhanced color saturation and emission efficiency through synergistic material properties

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If phosphorescent emissive molecules are used for full color display, then color rendering is improved, but material stability and device longevity worsen

Engineering Contradiction:

Improvecolor renderingVSAvoidmaterial stability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

Host materials are introduced as intermediaries that accommodate phosphorescent emitters and facilitate efficient energy transfer. The host materials provide a stable matrix that protects the phosphorescent molecules from degradation while maintaining their emission properties

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes multiple parameters including triplet energy levels, HOMO-LUMO energy gaps, and dopant concentrations to enhance both color rendering and material stability. By carefully tuning these parameters, the device achieves saturated colors while improving emitter longevity

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If white OLED with color filters is used, then device structure is simplified, but emission efficiency and color accuracy deteriorate

Engineering Contradiction:

Improvestructure simplicityVSAvoidemission efficiency

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

Instead of using a white OLED with color filters (subtractive color method), the patent inverts the approach by using individually tuned emissive layers that directly emit saturated colors (additive color method). This eliminates the need for color filters and improves emission efficiency while achieving full-color display capability

Inventive Principle:

Principle #13The other way round (Inversion)

4Ease of manufacture

If conventional OLED materials are used, then manufacturing cost is reduced, but emission brightness and color accuracy worsen

Engineering Contradiction:

Improvemanufacturing costVSAvoidbrightness

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent systematically optimizes material parameters including emitter concentration, host-guest ratios, and layer thicknesses to maximize brightness and color accuracy. These parameter optimizations enable conventional manufacturing processes to produce high-performance displays without requiring expensive advanced fabrication techniques

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 approach improves the efficiency and longevity of OLEDs by stabilizing emissive materials and reducing aging, enabling the production of high-quality, full-color displays with enhanced color accuracy and brightness.

Implementation Method 1

an enhancement layer that includes a plasmonic material for surface plasmon resonance

Methodology Applied

Scientific EffectSurface plasmon resonance: Resonance

Implementation Method 2

OLEDs make use of thin organic films that emit light when voltage is applied across the device

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS20240431171A1Organic electroluminescent devices

Publication Date: 2024.12.26 UNIVERSAL DISPLAY CORP

AI summary

Device structures are provided that include one or more plasmonic OLEDs and zero or more non-plasmonic OLEDs. Each plasmonic OLED includes an enhancement layer that includes a plasmonic material which exhibits surface plasmon resonance that non-radiatively couples to an organic emissive material and transfers excited state energy from the emissive material to a non-radiative mode of surface plasmon polaritons in the plasmonic OLED.