Depositable Ionic Iridium Complexes for Stable OLED Emission
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Solution Overview
Problem
Existing organic electroluminescent devices face issues with fluorescent quenching, crystallization, and the instability of light-emitting layers, particularly in synthesizing stable dark-blue phosphorescent materials, and the limited universality of depositable ionic complexes for use in electronic devices due to poor volatilization properties.
Innovation Solution
Development of a series of depositable ionic Iridium complexes with a tetraphenylborate derivative anion, which reduces interactivity between anions and cations, enhancing electrical charge transport and allowing for the production of high-efficiency OLEDs emitting blue to red light by doping the organic light-emitting layer with these complexes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ionic material is used as light-emitting material, then good redox properties and device stability are achieved, but poor volatilization properties prevent use in evaporation-deposition
Solution Approach 1:
The patent creates composite ionic materials by combining cationic complexes with tetraphenylborate anions. This composite structure integrates the beneficial redox properties of ionic materials with improved volatilization characteristics, enabling both solution processing and evaporation-deposition manufacturing methods.
Solution Approach 2:
The patent modifies the chemical parameters of ionic materials by selecting specific cationic complexes and tetraphenylborate anions with appropriate molecular weights and structures. These parameter changes enhance the volatilization properties while preserving the good redox properties and device stability.
2Ease of manufacture
If fluorescent material is used in light-emitting layer, then device preparation is simplified, but fluorescent quenching and crystallization occur leading to reduced service life
Solution Approach 1:
The patent changes the material type from fluorescent to phosphorescent emitters, utilizing phosphorescence mechanisms to avoid fluorescent quenching. This parameter change maintains ease of device preparation while significantly improving service life by eliminating crystallization issues.
Solution Approach 2:
The patent employs simple organic ligands and straightforward synthesis routes to create stable phosphorescent complexes. These materials offer long device service life through their inherent stability while maintaining simple preparation processes.
3Reliability
If phosphorescent light-emitting material is used, then stable dark-blue light material can be synthesized, but synthesis complexity increases
Solution Approach 1:
The patent segments the synthesis process into modular steps using well-defined cationic complexes and tetraphenylborate anions. This segmentation simplifies the overall synthesis complexity while maintaining the ability to produce stable phosphorescent materials across different color ranges.
Solution Approach 2:
The patent develops a universal synthesis approach using tetraphenylborate anions that can be applied across multiple phosphorescent complex systems. This universal methodology reduces synthesis complexity while maintaining material stability and enabling dark-blue light emission.
4Ease of manufacture
If hexafluorophosphate anion is used in ionic complex, then depositability is achieved, but universality is limited
Solution Approach 1:
The patent replaces hexafluorophosphate anions with tetraphenylborate anions, which provide universal depositability across diverse cationic complex systems. This substitution enables the development of a broader range of phosphorescent emitters with different colors and properties while maintaining ease of deposition.
Solution Approach 2:
The patent creates versatile ionic complexes by combining various cationic complexes with tetraphenylborate anions. This composite approach achieves universal depositability across different material systems while enabling the synthesis of phosphorescent emitters spanning from blue to red light regions.
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 solution improves the stability and efficiency of OLEDs by reducing drive voltage and energy consumption, enabling the production of high-efficiency devices with extended lifespan and versatility in emitting colors from blue to red.
Implementation Method 1
the tetraphenylborate derivative anion can increase the electrical charge transport capability
Implementation Method 2
The organic light-emitting layer comprises a host material doped with the aforementioned depositable ionic organic functional material
Data Source
AI summary
The present invention relates to a depositable ionic organic functional material having a structure selected from the formulas (21) to (26). The depositable ionic organic functional material can be used in high-efficiency blue to red OLEDs. The present invention also relates to an organic electroluminescent device using the depositable ionic organic functional material as a dopant in the organic light-emitting layer thereof.