Iridium OLED Emitter Composition for Saturated Green Emission
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Solution Overview
Problem
Existing organic light emitting diodes (OLEDs) face challenges in achieving efficient and tunable emission of saturated colors, particularly in full color displays, due to limitations in the phosphorescent emissive molecules used.
Innovation Solution
A compound with the formula Ir(LA)n(LB)3-n is provided, where Ir is bonded to ring A through an Ir—C bond, and X is O, S, or Se. This compound is used in an organic light emitting diode (OLED) to enhance color emission efficiency and tunability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional organic emissive materials are used in OLEDs, then the device can be fabricated with flexible substrates and cost advantages, but the efficiency and stability for green emission are insufficient
Solution Approach 1:
The patent modifies the chemical structure of iridium complex emissive materials by changing ligand parameters (LA and LB ligands with specific R1-R5 substituents) to optimize phosphorescent emission properties for green light, thereby improving emission efficiency and stability while maintaining compatibility with flexible substrate fabrication processes
Solution Approach 2:
The invention uses composite organic-inorganic emissive materials consisting of iridium metal center coordinated with organic ligands (LA)n(LB)3-n, combining the benefits of organic materials (flexibility, low cost) with the high efficiency and stability of phosphorescent inorganic emitters
2Adaptability or versatility
If the organic emissive layer is designed to emit white light, then color can be filtered to produce saturated red, green and blue, but the wavelength tuning and emission efficiency are limited
Solution Approach 1:
The patent employs different ligand types (LA and LB) with specific substituent patterns (R1-R5 groups) to create localized optimization of emission properties within the emissive complex, enabling precise control over phosphorescent emission wavelength and efficiency for green light while maintaining overall molecular 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 use of the Ir(LA)n(LB)3-n compound in OLEDs leads to improved color emission efficiency and tunability, enabling the production of saturated red, green, and blue pixels, as well as white light emission, which is essential for full color displays.
Implementation Method 1
One application for phosphorescent emissive molecules is a full color display
Implementation Method 2
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Data Source
AI summary
A compound having the formula Ir(LA)n(LB)3-n, having the structureof Formula I is provided. In the structure of Formula I, each of A1 through A8 is independently carbon or nitrogen; at least one of A1 through A8 is nitrogen; ring B is bonded to ring A through a C—C bond; the iridium is bonded to ring A through an Ir—C bond; X is O, S, or Se; each of R1 through R5 are independently selected from a variety of substituents, which may be linked for form a ring; n is an integer from 1 to 3; and at least one R2 adjacent to ring C is not hydrogen. Formulations and devices, such as OLEDs, that include the first compound are also provided.