Purely Organic Molecules for OLED Emitter Stability
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Solution Overview
Problem
Existing organic light-emitting diodes (OLEDs) face challenges in achieving high efficiency, stability, and accurate color reproduction, particularly in the green spectral range.
Innovation Solution
Development of a new class of purely organic molecules that do not contain metal ions but may include metalloids like B, Si, Sn, Se, and Ge, which exhibit emission maxima in the sky blue, green, or yellow spectral range and possess high photoluminescence quantum yields, including thermally activated delayed fluorescence (TADF).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal complexes are used as emitter materials in OLEDs, then high efficiency can be achieved, but device stability deteriorates and color reproduction accuracy is compromised
Solution Approach 1:
The patent removes metal ions from the emitter material composition, extracting the harmful element (metal) while retaining the desirable light-emitting function through purely organic compounds. This extraction resolves the contradiction by eliminating the source of instability and color reproduction issues while maintaining efficiency through the organic emitter's intrinsic properties
Solution Approach 2:
The patent employs composite organic structures combining electron-donating and electron-accepting moieties in a single molecule to achieve both high efficiency and stability. The composite organic structure replaces metal complexes, providing the necessary electronic properties for efficient emission without the stability compromises associated with metal-containing materials
2Productivity
If metal complexes are used as emitter materials in OLEDs, then high efficiency can be achieved, but color reproduction accuracy deteriorates
Solution Approach 1:
By removing metal ions from the emitter material, the patent eliminates the broad emission spectra and color instability inherent in metal complexes. The purely organic emitter provides sharp, well-defined emission peaks that accurately reproduce visible colors, simultaneously maintaining high emission efficiency through the optimized molecular structure
Solution Approach 2:
The patent changes the fundamental chemical composition parameters from metal-containing complexes to purely organic structures. This parameter change enables precise control over emission wavelength and spectral shape, achieving accurate color reproduction while maintaining the efficiency needed for practical OLED applications
3Reliability
If purely organic molecules without metal ions are used, then device stability is improved, but emission efficiency deteriorates
Solution Approach 1:
The patent optimizes key molecular parameters including the choice of electron-donating and electron-accepting moieties, their connectivity, and the overall molecular geometry. These parameter changes enable the purely organic emitter to achieve high photoluminescence quantum yield and efficient electroluminescence, eliminating the efficiency drawback traditionally associated with metal-free organic emitters
Solution Approach 2:
The patent designs composite organic molecules that integrate specific electron-donating groups with electron-accepting groups in a structured arrangement. This composite structure facilitates efficient charge injection, exciton formation, and radiative decay, achieving high emission efficiency while maintaining the stability advantages of metal-free organic materials
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
These organic molecules enhance the efficiency and stability of OLEDs, allowing for more accurate reproduction of visible colors and higher resolution in displayed images, while also enabling hyper-fluorescence by combining with fluorescence emitters.
Implementation Method 1
The molecules of the invention exhibit in particular thermally activated delayed fluorescence (TADF)
Implementation Method 2
The organic molecules preferably exhibit emission maxima between 470 and 580 nm, preferably between 490 and 560 nm, more preferably between 500 and 560 nm, even more preferably between 510 and 550 nm, and most preferably between 520 and 540 nm. The photoluminescence quantum yields of the organic molecules according to the invention are preferably equal to or higher than 10%
Data Source
Figure 1~2
AI summary
The invention relates to a light-emitting organic molecule, in particular for the application in optoelectronic devices. According to the invention, the organic molecule has - a first chemical moiety with a structure of Formula I and - a second chemical moiety with a structure of Formula II, wherein W is the binding site of a single bond linking the first chemical moiety to the second chemical moiety, L is a linking group with a structure of Formula BN-I, wherein the dashed lines denote the binding sites as indicated in Formula I, and # represents the binding site of the first chemical moiety to the second chemical moiety.