Light-Emitting Element Polymer Layers for Balanced Carrier Transport

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Solution Overview

Problem

Existing light-emitting devices suffer from reduced luminous efficiency due to significant differences in electron and hole mobility, leading to imbalanced carrier transport.

Innovation Solution

Incorporating a first polymer with a polysiloxane bond in the main chain and a π-conjugated electron pair in the side chain in the hole transport layer, and a second polymer with a polysiloxane bond in the main chain in the electron transport layer, to enhance carrier balancing by promoting hole and electron mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional carrier transport materials are used, then device structure is simple, but carrier balancing is poor due to large difference in electron and hole mobility

Engineering Contradiction:

Improvecarrier balancingVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses composite materials by combining metal oxide nanoparticles with organic polymers to create carrier transport layers with balanced electron and hole mobility. The metal oxide nanoparticles provide one type of carrier transport while the organic polymer provides complementary transport properties, achieving carrier balancing through material composition rather than structural complexity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the physical and chemical parameters of the carrier transport materials by controlling the particle size, concentration, and surface treatment of metal oxide nanoparticles. By adjusting these parameters, the electron and hole mobility can be tuned to achieve balanced carrier transport without complicating the device structure.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If metal oxide nanoparticles are used to improve carrier balancing, then luminous efficiency increases, but surface hydroxy groups may cause harmful effects

Engineering Contradiction:

Improveluminous efficiencyVSAvoidsurface hydroxy groups

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful surface hydroxy groups of metal oxide nanoparticles into beneficial functional groups through chemical treatment. The hydroxy groups are transformed into groups that enhance carrier transport and exciton recombination, turning what was initially a harmful surface property into an advantage for improving luminous efficiency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces organic polymers as intermediary materials that bond with metal oxide nanoparticles. These polymer intermediaries mediate between the metal oxide surface and the excitons, facilitating efficient energy transfer while preventing direct interaction between hydroxy groups and excitons that would cause harmful effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If carrier transport is enhanced by adding materials, then mobility improves, but drive voltage may increase

Engineering Contradiction:

Improvecarrier mobilityVSAvoiddrive voltage

Core Design Contradiction:

SpeedVSStress or pressure

Solution Approach 1:

The patent optimizes parameters such as nanoparticle concentration, size distribution, and organic polymer molecular weight to achieve high carrier mobility at low drive voltages. By carefully controlling these parameters, the material achieves efficient carrier transport without requiring high electric fields, thus avoiding increased drive voltage.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality variations in the carrier transport layer by distributing metal oxide nanoparticles and organic polymers in specific configurations. This local optimization allows different regions to contribute differently to carrier transport, achieving high overall mobility while maintaining low drive voltage through efficient local charge carrier pathways.

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

Improves carrier balancing, increases luminous efficiency, and maintains durability without increasing drive voltage, by chemically bonding metal oxide nanoparticles with polymers to eliminate surface hydroxy groups and facilitate efficient exciton recombination.

Implementation Method 1

a first polymer containing a polysiloxane bond in a main chain and containing a functional group including a π-conjugated electron pair in a side chain of the first polymer

Methodology Applied

Scientific Effectπ-conjugation:

Implementation Method 2

chemically bonding metal oxide nanoparticles with polymers to eliminate surface hydroxy groups and facilitate efficient exciton recombination

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

a light-emitting layer provided between the first electrode and the second electrode

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS12369450B2Light-emitting element

Publication Date: 2025.07.22 SHARP KK

AI summary

A light-emitting element includes an anode electrode, cathode electrode, an EML, and an HTL. The HTL includes a hole transport material, and a first polymer containing a polysiloxane bond in the main chain and having a functional group including a π-conjugated electron pair in a side chain of the first polymer.