Ladder-Type Compounds for OLED Charge Transport

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current organic electroluminescence devices lack materials with improved performance for charge transport and exciton blocking, particularly for phosphorescence and fluorescence emitters, which affect operational voltage and lifetime.

Innovation Solution

Development of specific ladder-type compounds with a unique combination of heteroatoms (N, O) and a specific connection of condensed rings, suitable for use as host, charge transport, or exciton blocking materials in organic electronic devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic compounds are used in electroluminescence devices, then the device structure is simpler, but the charge transport balance and exciton blocking performance are insufficient

Engineering Contradiction:

Improvecharge transport balance and exciton blocking performanceVSAvoidmolecular structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite molecular structures combining multiple heteroatoms (N, O, S) within single ladder-type compounds. These compounds integrate electron-transporting and hole-transporting capabilities along with exciton blocking functions into unified molecular architectures, achieving balanced charge transport without requiring separate material layers.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent systematically varies molecular parameters including heteroatom composition, ring condensation patterns, and substituent groups on the ladder-type core structure. These parameter changes enable optimization of charge transport balance, exciton blocking efficiency, and device performance while maintaining structural feasibility.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If existing host materials are used, then the material selection is simpler, but the operational voltage and device lifetime are not optimized

Engineering Contradiction:

Improveoperational voltageVSAvoidmaterial diversity

Core Design Contradiction:

Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The patent modifies key molecular parameters of host materials including the type and arrangement of heteroatoms (N, O, S), the degree of ring condensation, and the nature of substituent groups. These parameter changes directly influence the HOMO-LUMO energy levels, enabling optimization of operational voltage while extending device lifetime through improved charge transport and exciton management.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11616201B2Specific ladder type compounds for organic light emitting devices

Publication Date: 2023.03.28 IDEMITSU KOSAN CO LTD

AI summary

The present invention relates to a compound of formula (I), wherein R1, R2, R3 and R4 are each independently hydrogen or Ra, with proviso that a pair of two substituents selected from R1 and R2, R2 and R3, and R3 and R4 is linked to one another and forms a group of formula (II); a material for an organic electroluminescence device comprising at least one compound of formula (I); an organic electroluminescence device which comprises an organic thin film layer be-tween an anode and a cathode, wherein the organic thin film layer comprises one or more layers and comprises a light emitting layer, and at least one layer of the organic thin film layer comprises at least one compound of formula (I); and an electronic equipment comprising the inventive organic electroluminescence device.