π-Conjugated Boron Compound for OLED Host Material Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic electroluminescence elements face challenges in achieving compatibility for carrier tolerance and exciton resistance as host materials, and suffer from thermal instability and poor hole transporting properties due to the high electrophilicity of boron-containing compounds, which affects their performance and longevity.
Innovation Solution
A π-conjugated boron compound with a specific structure represented by Formula (1) is used, providing improved planarity and rigidity, enhancing thermal and electrochemical stability, and enabling both electron and hole transport capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If boron-containing compounds are used as electron transport materials due to high electron acceptor properties, then electron transporting properties are improved, but thermal stability deteriorates due to high electrophilicity
Solution Approach 1:
The patent changes the chemical parameters of the boron-containing compound by introducing specific substituents (aromatic rings, oxygen atoms in joint portions) to modify the electrophilicity and thermal stability while maintaining electron transporting properties. This resolves the contradiction by adjusting molecular structure parameters rather than changing the fundamental boron-based electron acceptor mechanism.
Solution Approach 2:
The patent creates a composite molecular structure combining boron atoms with aromatic rings and oxygen-containing joint portions. This composite structure achieves both high electron acceptor properties from boron and improved thermal stability from the aromatic framework, resolving the contradiction between electron transporting properties and thermal stability.
2Reliability
If heteroatom is only electron acceptor boron atom, then electron transporting properties are improved, but hole transporting property deteriorates and carrier recombination occurs at interface
Solution Approach 1:
The patent makes the boron-containing compound multi-functional by designing it to perform both electron accepting and hole transporting functions. The aromatic ring structures and oxygen-containing joint portions enable hole transport while the boron atom maintains electron accepting capability, allowing the single material to function in both electron transport and hole transport layers.
Solution Approach 2:
The patent modifies the electronic parameters of the boron-containing compound by introducing electron-donating aromatic groups that enable hole transport capability while preserving the electron accepting property of boron. This dual functionality resolves the contradiction between electron and hole transporting properties.
3Strength
If methyl moiety protrudes perpendicularly to aromatic ring, then steric protection is provided, but π-π stacking is inhibited and carrier transportability deteriorates
Solution Approach 1:
The patent replaces the perpendicular methyl moiety with planar aromatic ring structures that maintain steric protection while allowing π-π stacking. The aromatic rings provide a flat, extended surface that enables face-to-face stacking between molecules, facilitating carrier transport while the ortho-substitution pattern maintains steric protection of the boron atom.
Solution Approach 2:
The patent creates a composite structure where aromatic rings replace the methyl moiety, combining the steric protection function with the additional benefit of π-π stacking capability. This composite aromatic structure resolves the contradiction by providing both protection and transport pathways.
4Ease of manufacture
If planar immobilization from all directions is not attempted, then synthesis is simpler, but rigidity of ring is insufficient and electrochemical stability deteriorates
Solution Approach 1:
The patent applies local quality by introducing oxygen atoms specifically at the joint portions (ortho positions) of the aromatic rings connected to boron. This localized structural modification provides rigidity and electrochemical stability at the critical bonding regions without requiring complete planar immobilization from all directions, thus maintaining reasonable synthesis simplicity while achieving the desired stability.
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
The π-conjugated boron compound improves the stability and performance of organic electroluminescence elements by facilitating carrier balance and transportability, leading to enhanced drive voltage and emission luminance.
Implementation Method 1
a π-conjugated boron compound having a structure represented by Formula (1)
Data Source
AI summary
An organic electroluminescence element material contains a π-conjugated boron compound having a structure represented by Formula (1),wherein, X1 and X2 each independently represent O, S, or N—Y1, Y1 represents an alkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group, when there are a plurality of Y1s the plurality of Y1s may be the same or different, R1 to R9 each independently represent a hydrogen atom or a substituent.