Iridium OLED Emitters for Saturated RGB Color Purity
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Solution Overview
Problem
Existing organic light emitting diodes (OLEDs) face challenges in achieving saturated colors, particularly in full color displays, where conventional materials may not efficiently produce red, green, and blue pixels with high color purity.
Innovation Solution
The use of a compound of formula Ir(LA)2LC, where each ligand LA is coordinated to Ir to form a 5-membered chelate, and LC has a specific structure, is proposed. This compound is integrated into the organic layer of OLEDs to enhance color emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional organic materials are used in OLEDs, then the device structure and materials are relatively simple and inexpensive, but the color emission saturation and purity are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of organic compounds through specific ligand combinations (LA and LC ligands coordinated to Ir center) and substituent groups (RA, RB, Ra1, Rb1, Rc1). These structural parameter changes enable the emission of saturated red, green, and blue colors with high color purity, directly resolving the contradiction between color saturation and material simplicity.
Solution Approach 2:
The patent employs composite materials by creating organometallic compounds with a central Ir atom coordinated to specific LA and LC ligands. This composite structure combines metal center with organic ligands to achieve enhanced color emission properties that cannot be obtained with simple organic materials alone, while maintaining solution processability and fabrication advantages.
2Manufacturing precision
If conventional materials are used, then fabrication is easier and costs are lower, but color purity and saturation for red, green, and blue pixels are not achieved
Solution Approach 1:
The patent achieves high color purity through precise parameter changes in molecular structure, specifically the coordination geometry around Ir center and the electronic properties of LA and LC ligands. These parameter optimizations enable saturated color emission while the compounds remain solution-processable, maintaining ease of manufacture through conventional OLED fabrication techniques.
3Illumination intensity
If white OLED with absorption filters is used, then color can be produced, but emission efficiency and color saturation are reduced compared to direct emission
Solution Approach 1:
The patent extracts the color generation function from the filtering process and implements it directly in the emission layer. By using Ir-based organometallic compounds with specific LA and LC ligands that directly emit saturated red, green, and blue colors, the patent eliminates the need for white backlight and absorption filters, thereby removing energy loss associated with filtering and achieving higher color emission efficiency.
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 incorporation of the Ir(LA)2LC compound into OLEDs improves the emission of saturated colors, leading to more vivid and accurate color reproduction in displays, thereby addressing the limitations of conventional OLED technologies.
Implementation Method 1
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Implementation Method 2
One application for phosphorescent emissive molecules is a full color display
Data Source
AI summary
Provided are compounds of formula Ir(LA)2LC where:each ligand LA can be the same or different and has Formula IAlso provided are formulations comprising these iridium complexes comprising pyridine-azole ligands. Further provided are OLEDs and related consumer products that utilize these iridium complexes comprising pyridine-azole ligands.