Iridium Complex Ligand Design for Saturated OLED Emission
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Solution Overview
Problem
Existing organic light emitting diodes (OLEDs) face challenges in achieving saturated red, green, and blue colors for full-color displays, which is crucial for high-quality display technology.
Innovation Solution
A compound with the formula Ir(LA)n(LB)m(LC)o is introduced, where LA, LB, and LC are specific ligands that contribute to the emission properties of the OLED, enabling the production of saturated colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional materials are used in OLEDs, then device fabrication is simpler and cost is lower, but color saturation is insufficient for full-color displays
Solution Approach 1:
The patent modifies the chemical structure parameters of the emitter molecules by incorporating specific ligand combinations (LA, LB, LC) with defined coordination modes to the iridium center. This changes the electronic and optical properties of the material, enabling saturated red, green, and blue emissions while maintaining reasonable device fabrication complexity
Solution Approach 2:
The invention uses composite ligand structures where LA (Formula IA), LB (Formula IB), and LC (bidentate ligand) work together in specific stoichiometric ratios (n+m+o=3) to create an iridium complex with enhanced color saturation properties that neither component could achieve alone
2Productivity
If white OLED with absorption filters is used, then device structure is simpler, but emission efficiency is reduced due to light absorption losses
Solution Approach 1:
Instead of using a single white emissive layer with absorption filters, the patent segments the emission function into separate saturated red, green, and blue emitting components within the organic layer. This eliminates the need for absorption filters and reduces light loss, improving overall emission efficiency
Solution Approach 2:
The invention directly generates saturated red, green, and blue emissions through the photophysical properties of the iridium complex and its ligand environment, eliminating the need for color conversion filters and improving emission efficiency by avoiding absorption losses
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)m(LC)o compound in OLEDs enhances color saturation and efficiency, allowing for the creation of high-quality full-color displays with improved performance.
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
A compound having a formula of Ir(LA)n(LB)m(LC)o is provided, where LA has a structure of Formula IA,LB has a structure of Formula IB,and LC is a bidentate ligand. In formula Ir(LA)n(LB)m(LC)o, Formula IA, and Formula IB: m, n, and o are integers and their sum is 3; each of Z1, Z2, Z3, Z4, and X1 to X12 is C or N; each of moiety A and moiety B is a monocyclic ring or a polycyclic fused ring system; the ring comprising Z3 and Z4 is a 5-membered heterocyclic ring; Y is as linking group; each R, R′, R″, R1, R2, R3, R4, and R5 is hydrogen or a General Substituent; and at least one pair of R1 or one pair of R2 are joined to form moiety I, which is a heterocyclic moiety. Formulations, OLEDs, and consumer products containing the compound are also provided.