OLED Electron Transport Compound with Phosphine Oxide Groups

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Solution Overview

Problem

Existing electron transport layer materials for OLEDs have lower triplet energy and electron mobility, leading to reduced efficiency and poor thermal stability, hindering their commercialization.

Innovation Solution

A compound represented by Formula 1, where X is O or S, R1 and R2 are independently selected from aryl, heteroaryl, or —P(O)—R3R4, with specific substituents, is developed to enhance triplet energy, electron mobility, hole blocking, and thermal stability, and is used in the OLED structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing electron transport layer materials are used, then the OLED can be manufactured with current technology, but the triplet energy and electron mobility are insufficient leading to reduced efficiency

Engineering Contradiction:

ImproveOLED efficiencyVSAvoidmaterial performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent modifies the molecular structure parameters of electron transport layer materials by introducing specific substituents (R1-R6) including aryl, heteroaryl, and phosphine oxide groups. These structural parameter changes directly increase triplet energy levels and electron mobility, resolving the contradiction between manufacturability and performance efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite molecular structures combining multiple functional groups (X=O or S, aryl groups, heteroaryl groups, and phosphine oxide groups) within a single electron transport layer material. This composite approach simultaneously achieves high triplet energy, high electron mobility, and proper hole blocking capability, overcoming the limitations of existing single-function materials

Inventive Principle:

Principle #40Composite materials

2Productivity

If electron transport layer materials with improved triplet energy are developed, then OLED efficiency increases, but thermal stability deteriorates due to low glass transition temperature

Engineering Contradiction:

ImproveOLED efficiencyVSAvoidthermal stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent carefully adjusts molecular structure parameters including the selection of X (O or S), the types of aryl and heteroaryl groups, and the positioning of phosphine oxide groups. These parameter optimizations simultaneously achieve high triplet energy for efficiency while maintaining high glass transition temperatures for thermal stability, preventing material degradation during OLED operation

Inventive Principle:

Principle #35Parameter changes

3Productivity

If novel electron transport layer materials are developed to secure high triplet energy and electron mobility, then OLED efficiency improves, but the complexity of material synthesis and optimization increases

Engineering Contradiction:

ImproveOLED efficiencyVSAvoidmaterial structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent designs electron transport layer materials with multi-functional groups that simultaneously provide high triplet energy, high electron mobility, and hole blocking capability. This universal design approach consolidates multiple functions into a single material class, reducing the need for complex multi-layer structures and simplifying the overall OLED device architecture while maintaining high efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11345688B2Compound, preparing method therefor, and organic light emitting element comprising same

Publication Date: 2022.05.31 DAEGU GYEONGBUK INSTITUTE OF SCIENCE AND TECHNOLOGY

AI summary

The compound is represented by Formula 1. In Formula 1, X is O or S, and R1 and R2 are independently selected from the group consisting of aryl, heteroaryl and —P(O)—R3R4, where the aryl, heteroaryl and —P(O)—R3R4 are substituted or unsubstituted with 1 to 4 substituents selected from the group consisting of (C1-C4)alkyl, (C1-C4)alkoxy, aryl and heteroaryl. The “aryl” means a group consisting of 6 to 10 cyclic rings, and the “heteroaryl” means a group consisting of 5 to 14 cyclic rings having 1 to 4 heteroatoms selected from oxygen, sulfur and nitrogen (including quaternary nitrogen). R3 and R4 are independently selected from aryl or heteroaryl.