Phosphine Oxide Compound for OLED Electron Transport
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Solution Overview
Problem
Existing organic electronic devices, particularly OLEDs, face challenges in improving lifetime, driving voltage, and current efficiency due to limitations in phosphine-oxide electron transport materials, which also affect glass transition temperatures.
Innovation Solution
A novel compound represented by Formula (I) is introduced, comprising a phosphine oxide moiety combined with a structural moiety bound to an arylene or heteroarylene group, enhancing glass transition temperature and electron transport properties when used as an electron transporting host in OLEDs, particularly when combined with additives like metals or metal complexes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphine oxide electron transport materials are used in OLEDs, then electron transport function is achieved, but lifetime and driving voltage performance are insufficient
Solution Approach 1:
The patent modifies the molecular structure of phosphine oxide compounds by introducing specific substituents (R1-R6 groups including aryl, heteroaryl, and alkyl groups) and adjusting the core structure (rings B, C, D with anellated aromatic rings). These structural parameter changes optimize electron transport properties while improving lifetime and reducing driving voltage requirements
Solution Approach 2:
The patent creates composite electron transport materials by combining phosphine oxide moieties with various aromatic and heteroaromatic groups. The compound structure integrates multiple functional groups (X=O, S, or Se; aryl groups; heteroaryl groups) to achieve synergistic effects that improve both reliability and power characteristics
2Productivity
If phosphine oxide electron transport materials are used, then electron transport capability is provided, but current efficiency remains insufficient
Solution Approach 1:
The patent optimizes current efficiency by adjusting molecular parameters including the choice of X (O, S, or Se), the aromatic ring systems (B, C, D), and substituent groups (R1-R6). These changes enhance electron mobility and reduce energy loss, improving overall current efficiency
Solution Approach 2:
The patent introduces specific local structural features such as anellated aromatic rings B and C, and strategically positioned substituent groups R3 and R4 on rings C and D. These localized structural modifications create optimal electron transport pathways that enhance current efficiency while minimizing energy loss
3Temperature
If conventional electron transport materials are used, then device operation is achieved, but glass transition temperatures are insufficient
Solution Approach 1:
The patent raises glass transition temperatures by modifying the molecular structure of phosphine oxide compounds. The introduction of rigid aromatic ring systems (anellated rings B and C) and various substituent groups (R1-R6 including aryl and heteroaryl groups) increases molecular rigidity and intermolecular interactions, thereby elevating glass transition temperatures and improving material 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 compound significantly improves the performance of OLEDs by increasing charge mobility, luminance efficiency, and reducing operating voltage, leading to enhanced cd/A efficiency and extended device lifetime.
Implementation Method 1
electrons injected from the cathode electrode move to the EML, via the ETL
Implementation Method 2
it has been found that a compound having the Formula (I)... is helpful to increase the glass transition temperature by several 10K
Implementation Method 3
The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted
Data Source
AI summary
The present invention relates to the compound represented by the general Formula (I):whereinX is selected from the group consisting of O, S and Se;R1 and R2 are independently selected from the group consisting of C1 to C12 alkyl, C6 to C20 aryl and C5 to C20 heteroaryl, wherein the respective C1 to C12 alkyl may optionally be substituted with C6-C20 aryl;L represents a single bond or is selected from the group consisting of C6 to C18 arylene or C2 to C20 heteroarylene;wherein the rings B, C and D may each be unsubstituted or substituted and B and C are anellated aromatic 6-membered rings;R3 and R4 are independently selected from the group consisting of unsubstituted or substituted C1 to C12 alkyl, unsubstituted or substituted C1 to C12 fluorinated alkyl, unsubstituted or substituted C6 to C20 aryl and unsubstituted or substituted C5 to C20 heteroaryl;wherein the substituents, if present in B, C, D, R3 and R4, are independently selected from the group consisting of C1-C20 linear alkyl, C3-C20 branched alkyl, C3-C20 cyclic alkyl, C1-C20 linear alkoxy, C3-C20 branched alkoxy, linear fluorinated C1-C12 alkyl, linear fluorinated C1-C12 alkoxy, C3-C12 branched fluorinated cyclic alkyl, C3-C12 fluorinated cyclic alkyl, C3-C12 fluorinated cyclic alkoxy, CN, C6-C20 aryl, C2-C20 heteroaryl, OR, SR, (C═O)R, (C═O)NR2, SiR3, (S═O)R, (S═O)2R, CR═CR2, Fluorine, NR2, NO2;wherein R is independently selected from C1-C20 linear alkyl, C1-C20 alkoxy, C1-C20 thioalkyl, C3-C20 branched alkyl, C3-C20 cyclic alkyl, C3-C20 branched alkoxy, C3-C20 cyclic alkoxy, C3-C20 branched thioalkyl, C3-C20 cyclic thioalkyl, C6-C20 aryl and C3-C20 heteroaryl; andR3 and R4 may or may not be connected with each other via a single bond, an organic semiconducting layer comprising the same, an organic electronic device comprising the organic semiconducting layer and a display device or a lighting device comprising the same.