Organic Electroluminescent Host Combinations for Balanced Carrier Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic electroluminescent devices face challenges in achieving high luminous efficiency and/or long lifespan, with existing materials not adequately addressing the imbalance between hole and electron mobilities.
Innovation Solution
A combination of compounds represented by formulas 1 and 2 is used as host materials, where formula 1 provides slow hole mobility and formula 2 offers fast electron mobility, enhancing exciton formation and improving transport properties in the light-emitting layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compound with very deep HOMO is used as host material, then hole mobility is slow, but luminous efficiency improvement is required
Solution Approach 1:
The patent uses a composite host system comprising two distinct compounds: Compound 1 (with very deep HOMO providing slow hole mobility) and Compound 2 (with fast hole mobility). This composite approach allows the system to benefit from both the deep HOMO level for high luminous efficiency and the fast hole mobility from Compound 2, resolving the contradiction between these two properties.
Solution Approach 2:
The patent assigns different functional roles to different components of the host system. Compound 1 primarily provides the deep HOMO level for efficient exciton formation, while Compound 2 specifically addresses the hole mobility issue. This division of functional responsibilities allows each component to optimize its specific contribution without compromising the other.
2Reliability
If phosphorous materials are used to achieve high luminous efficiency, then lifespan is improved, but the imbalance between hole and electron mobility remains
Solution Approach 1:
The patent changes the mobility parameters by selecting compounds with specifically tuned properties. Compound 1 is chosen for its very deep HOMO level, while Compound 2 is selected for its fast hole mobility. This parameter optimization allows the system to maintain the benefits of phosphorous materials (high luminous efficiency and lifespan) while correcting the mobility imbalance through careful material selection.
Data Source
AI summary
The present disclosure relates to a plurality of host materials comprising a first host material comprising a compound represented by the following formula 1, and a second host material comprising a compound represented by the following formula 2, and an organic electroluminescent device comprising the same. By comprising a specific combination of compounds as a host material, it is possible to provide an organic electroluminescent device having higher luminous efficiency and/or improved lifespan characteristics compared to conventional organic electroluminescent devices.