Polymer Compound for Electroluminescent Devices Enhancing Hole Injection

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Solution Overview

Problem

Current electroluminescent devices, particularly quantum dot electroluminescent devices, face challenges in achieving long luminescence lifespan and sufficient luminous efficiency due to limitations in hole transport and injection properties of existing materials.

Innovation Solution

A polymer compound with a specific structural unit, represented by Chemical Formula (1), is introduced, which includes an aromatic hydrocarbon group substituted with an alkyl group having a carboxyl group, enhancing hole injection properties and increasing the triplet energy level, thereby improving luminescence lifespan and luminous efficiency while allowing for low driving voltage operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional hole transport materials are used in quantum dot electroluminescent devices, then the device structure is simple and manufacturing is easier, but the luminescence lifespan is short and luminous efficiency is insufficient

Engineering Contradiction:

Improveluminescence lifespanVSAvoidpolymer compound structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies the chemical structure parameters of hole transport materials by introducing specific aromatic hydrocarbon groups with carboxyl-substituted alkyl groups. This structural parameter change enhances hole injection properties and triplet energy levels, directly improving luminescence lifespan and efficiency without fundamentally changing the device architecture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite polymer compounds combining multiple functional moieties (aromatic hydrocarbon groups, carboxyl groups, alkyl chains) within a single material system. This composite structure achieves synergistic effects that simultaneously improve hole transport, hole injection, and triplet energy level, resolving the contradiction between performance and structural simplicity

Inventive Principle:

Principle #40Composite materials

2Reliability

If existing hole transport materials are used, then the manufacturing process is straightforward, but the hole injection properties and hole transport properties are insufficient

Engineering Contradiction:

Improvehole injection propertiesVSAvoidmaterial synthesis complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces specific functional groups (carboxyl-substituted alkyl groups on aromatic hydrocarbon cores) at strategic locations within the polymer structure. This local functionalization enhances hole injection properties at the interface without requiring complete restructuring of the entire material system, balancing performance improvement with manufacturing feasibility

Inventive Principle:

Principle #3Local quality

3Productivity

If conventional materials are used in electroluminescent devices, then the device operation is simple, but the luminous efficiency is low and driving voltage is high

Engineering Contradiction:

Improveluminous efficiencyVSAvoiddriving voltage

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The patent optimizes key material parameters including HOMO/LUMO energy levels, hole mobility, and triplet energy level through specific molecular design. These parameter optimizations enable efficient charge transport and recombination at lower voltages while maximizing luminous efficiency, directly addressing the contradiction between productivity and power consumption

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 polymer compound significantly enhances the luminescence lifespan and luminous efficiency of electroluminescent devices by improving hole injection and mobility, achieving high durability and efficient light emission under low driving voltage.

Implementation Method 1

increasing the triplet energy level, thereby improving luminescence lifespan and luminous efficiency

Methodology Applied

Scientific EffectTriplet energy level:

Implementation Method 2

enhancing hole injection properties and increasing the triplet energy level

Methodology Applied

Scientific EffectHole injection:

Implementation Method 3

improving hole injection and mobility

Methodology Applied

Scientific EffectHole transport:

Implementation Method 4

An EL device is a light emitting device, which includes a thin film with a thickness of several nanometers to several hundred nanometers between an anode and a cathode

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 5

Because quantum dots are very small in size, the surface area per unit volume is large. For this reason, most of the atoms are present on the surface of the nanocrystals, and exhibit quantum confinement effects. Due to the quantum confinement effect, adjustments to the quantum dot, such as changes to quantum dot size, can alter the emission wavelength and improve color purity

Methodology Applied

Scientific EffectQuantum confinement effect:

Data Source

PatentUS20240158566A1Polymer compound, and electroluminescent device material and electroluminescent device including polymer compound

Publication Date: 2024.05.16 SAMSUNG DISPLAY CO LTD

AI summary

A polymer compound for use in an electroluminescent device may improve the durability (particularly the luminescence lifespan). The polymer compound includes Structural Unit (A) represented by Chemical Formula (1).In Chemical Formula (1), the definition of each substituent is as described in the detailed description.