Hole Transport Polymers for OLED Device Lifetime

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

There is a continuing need for effective charge transport materials in organic photoactive electronic devices, such as OLEDs, where existing materials may not provide optimal performance in terms of device efficiency and operational lifetime.

Innovation Solution

The development of polymers and copolymers based on specific monomers with fluorenyl or carbazole groups, which can be used as hole transport materials, are synthesized through Yamamoto polymerization, offering improved properties and longer lifetimes in electronic devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing charge transport materials are used in OLEDs, then device fabrication can proceed with conventional materials, but device operational lifetime and efficiency are not optimal

Engineering Contradiction:

Improvedevice operational lifetimeVSAvoidmaterial performance optimization

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent modifies the chemical structure of hole transport materials by incorporating specific substituents (R groups including alkyl, aryl, heteroaryl) and varying molecular weight parameters to optimize device lifetime and efficiency. The polymer structures use repeat units with adjustable parameters that allow fine-tuning of material properties for improved OLED performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite polymer structures combining hole transport functionality with specific side chain architectures (including options for R′ crosslinkable groups and R′′ substituents). These composite molecular structures integrate multiple functional elements within a single material system to achieve both improved lifetime and efficiency

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional hole transport materials are used, then material synthesis follows established procedures, but charge transport efficiency is insufficient

Engineering Contradiction:

Improvecharge transport efficiencyVSAvoidpolymer structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the hole transport material into distinct functional segments: a core repeat unit providing charge transport functionality, and side chains (R groups) that can be independently optimized. This segmentation allows the main chain to focus on charge transport while side chains can be tailored for solubility, processing, and device performance

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies local quality optimization by allowing different R groups at different positions on the polymer backbone. Each position can have substituents specifically optimized for its local environment, enabling enhanced charge transport at critical locations while maintaining overall material processability

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8487055B2Hole transport polymers

Publication Date: 2013.07.16 LG CHEM LTD

AI summary

There is provided a polymer made from a monomer having Formula I:where:R and Y are independently selected from the group consisting of H, D, alkyl, fluoroalkyl, aryl, fluoroaryl, alkoxy, aryloxy, NR″2, R′,R′ is a crosslinkable group;R″ is independently selected from the group consisting of H, alkyl, fluoroalkyl, aryl, fluoroaryl, and R′;X is a leaving group;Z is C, Si, or N;Q is (ZR″n)b;a is an integer from 0 to 5;b is an integer from 0 to 20;c is an integer from 0 to 4;q is an integer from 0 to 7; andn is an integer from 1 to 2.