Iridium Complex Purification for Longer-Lived OLED Emission Layers
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Solution Overview
Problem
Existing organic light emitting devices containing iridium complexes suffer from reduced device lifetime due to the presence of isomers, which can be minimized by decreasing the amount of these isomers in the composition.
Innovation Solution
A method to manufacture an iridium complex composition with a reduced isomer content through sublimation purification, recrystallization, dispersion washing, and column cleanup, resulting in a composition ratio of isomers less than 0.6%, which is further optimized to 0.2% or less, and incorporating the complex into the organic compound layer of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the iridium complex is synthesized by the conventional method, then the light emission efficiency is high, but the device lifetime is reduced due to isomer formation
Solution Approach 1:
The patent applies preliminary action by performing purification steps (sublimation, recrystallization, column chromatography) on the iridium complex before it is incorporated into the organic light emitting device. This removes isomers from the composition in advance, preventing them from causing device degradation while preserving the high light emission efficiency of the pure iridium complex.
Solution Approach 2:
The patent extracts the harmful isomers from the iridium complex composition through multiple purification techniques. By separating and removing the isomer components while retaining the desired iridium complex, the patent eliminates the source of device lifetime reduction while maintaining the beneficial light emission properties.
2Reliability
If the isomer content is reduced through purification, then the device lifetime is extended, but the manufacturing complexity increases
Solution Approach 1:
The patent performs all necessary purification steps (sublimation, recrystallization, column chromatography) before the iridium complex is used in device fabrication. By completing the complex purification process in advance, the actual device manufacturing process is simplified, and the purified complex can be directly incorporated without additional purification steps during device assembly.
3Manufacturing precision
If multiple purification steps are performed, then the isomer content decreases to 0.2% or less, but the manufacturing time increases
Solution Approach 1:
The patent executes the multi-step purification sequence (sublimation followed by recrystallization and column chromatography) as a preliminary process before device fabrication. This concentrates the time investment in purification at the beginning, allowing for precise isomer control (0.2% or less) while enabling faster subsequent device manufacturing without repeated purification cycles.
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 method extends the device lifetime of organic light emitting devices by minimizing isomer content, leading to high-luminance optical output and improved durability.
Implementation Method 1
A method to manufacture an iridium complex composition with a reduced isomer content through sublimation purification
Implementation Method 2
A method to manufacture an iridium complex composition with a reduced isomer content through sublimation purification, recrystallization
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
The present disclosure provides a composition that contains an iridium complex and an isomer of the iridium complex, in which the amount of the isomer of the iridium complex is decreased. The iridium complex is a homo-N-trans (HNT) iridium complex having an iridium atom, and a first ligand, a second ligand, and a third ligand that are bonded to the iridium atom. The isomer has an iridium atom, a fourth ligand, a fifth ligand, and the third ligand. The composition ratio of the isomer relative to a total of the iridium complex and the isomer is 1.0% or less.