Copper(I) Complexes for OLED Emitter Stability
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Solution Overview
Problem
Current OLED technologies face challenges with the long-term stability, thermal stability, chemical stability to water and oxygen, reproducibility in manufacturing, achieving high efficiency at high current densities, achieving very high luminances, high cost, toxicity, and complex synthesis of triplet emitter materials.
Innovation Solution
Copper(I) complexes of the Cu2X2(E∩N*)3 form, where X is Cl, Br, or I, E is R2As or R2P, and N*∩E is a bidentate ligand with an imine functional group, offering improved solubility, reduced synthesis complexity, and lower toxicity, enabling high emission quantum yield and short emission decay times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If triplet emitter materials are used to achieve high emission quantum yield, then light yield and efficiency are improved, but long-term stability, thermal stability, and chemical stability to water and oxygen deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by using copper(I) complexes with specific ligand combinations (N*-E bidentate ligands where N* is an imine nitrogen and E is a phosphorus or arsenic atom). This parameter change maintains high emission quantum yield while improving stability properties compared to traditional triplet emitters
Solution Approach 2:
The invention employs composite material structures by combining copper(I) centers with specially designed bidentate ligands containing both imine nitrogen and phosphorus/arsenic atoms. This composite approach creates a material that simultaneously achieves high emission efficiency and improved stability against degradation
2Loss of energy
If traditional triplet emitter materials are used, then high emission efficiency is achieved, but synthesis complexity and cost increase
Solution Approach 1:
The ligand structure is segmented into distinct functional components: the N*-E bidentate ligand combines an imine nitrogen donor with a phosphorus or arsenic donor in a single chelating unit. This segmentation simplifies synthesis by allowing modular construction of the ligand and straightforward complexation with copper(I), reducing overall synthesis complexity while maintaining high emission efficiency
3Illumination intensity
If high emitter concentrations are used to achieve very high luminances, then brightness is improved, but quenching effects occur
Solution Approach 1:
The patent changes the photophysical parameters of the emitter by using copper(I) complexes with N*-E ligands, which exhibit short emission decay times. This parameter change allows high emitter concentrations to be used without significant quenching, enabling very high luminances to be achieved while maintaining high emission quantum yield
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 copper(I) complexes provide a wide range of achievable emission colors, high emission quantum yield, and are usable in high emitter concentrations without quenching effects, reducing synthesis costs and toxicity while enhancing the performance and stability of OLEDs.
Implementation Method 1
In a middle layer, the emitter layer, which likewise consists of an organic material, there are additionally special emitter molecules at which, or close to which, the two charge carriers recombine and lead to uncharged but energetically excited states of the emitter molecules. The excited states then release their energy as bright emission of light
Implementation Method 2
Using organometallic complexes with high emission quantum yield (transitions including the lowermost triplet states to the singlet ground states), it is possible to achieve a particularly high efficiency of the device. These materials are frequently referred to as triplet emitters or phosphorescent emitters
Data Source
AI summary
The invention relates to an optoelectronic component having a copper(I) complex of the formula:wherein X is independently selected from Cl, Br and I; N*∩E or E∩N* is a bidentate ligand connected to a first Cu atom via an N atom and connected to a second Cu atom via an E group, or a monodentate ligand connected to a Cu atom via an E group, wherein E is R2As or R2P, wherein R is selected from alkyl, aryl, alkoxy, and phenoxy; N* is a part of an aromatic group comprising an imine functional group, wherein the aromatic group is selected from pyridyl, pyrimidyl, pyridazinyl, triazinyl, oxazolyl, thiazolyl, imidazolyl, and fused N-heteroaromatics, and wherein the imine functional group comprises the N atom double bonded to a carbon atom of the aromatic group; and ∩ is a carbon atom, which is likewise part of the aromatic group, connected to the N atom of said aromatic group and also connected to the E group via the As or P atom of the E group.