Organic Molecules for OLED Efficiency and Stability
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Solution Overview
Problem
Existing organic optoelectronic devices, such as OLEDs, face limitations in efficiency and stability due to the use of metal complex compounds, particularly in achieving high photoluminescence quantum yields and thermally activated delayed fluorescence in the blue, sky blue, and green spectral ranges.
Innovation Solution
Development of purely organic molecules with specific structures, characterized by emissions in the blue, sky blue, or green spectral range, exhibiting thermally activated delayed fluorescence (TADF) and photoluminescence quantum yields of 20% or more, which are used in optoelectronic devices to enhance efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal complex compounds are used as emitter materials in OLEDs, then device efficiency can be improved, but device stability deteriorates
Solution Approach 1:
The patent removes metal atoms from the emitter material structure, transitioning from metal complex compounds to purely organic molecules. This extraction of the problematic metal component eliminates the stability issues associated with metal-based emitters while maintaining the desired optoelectronic performance through carefully designed organic molecular structures featuring specific donor and acceptor units.
Solution Approach 2:
The patent employs composite molecular structures combining electron-donating units and electron-accepting units within single organic molecules. These composite organic structures, featuring combinations of heterocyclic aromatic rings and functional groups, achieve both high efficiency and stability by integrating multiple functional characteristics into purely organic frameworks without requiring metal centers.
2Ease of manufacture
If conventional emitter materials are used, then device manufacturing is simpler, but photoluminescence quantum yield is insufficient
Solution Approach 1:
The patent systematically modifies molecular parameters including HOMO-LUMO energy gaps, photoluminescence quantum yields, and emission wavelengths by adjusting the types and arrangements of donor and acceptor units. These parameter optimizations enable achievement of photoluminescence quantum yields of 20% or more while maintaining compatibility with standard OLED manufacturing processes.
3Productivity
If metal complex compounds are used to achieve thermally activated delayed fluorescence, then emission performance improves, but material complexity increases
Solution Approach 1:
The patent replaces complex, expensive metal complex materials with simpler, purely organic molecules that can be more easily synthesized and processed. The organic emitter materials use common heterocyclic building blocks and standard organic synthesis methods, eliminating the need for rare metals and complex coordination chemistry while achieving comparable or superior emission performance.
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 these organic molecules in OLEDs results in higher device efficiency and stability, with emission maxima within the desired spectral ranges, offering improved performance compared to conventional emitter materials.
Implementation Method 1
The organic molecules according to the invention are characterized by emissions in the blue, sky blue, or green spectral range. The photoluminescence quantum yields of the organic molecules according to the invention are in particular 20% and more. The molecules according to the invention in particular exhibit thermally activated delayed fluorescence (TADF).
Data Source
AI summary
An organic molecule for use in optoelectronic components is disclosed having a structure of Formula IwithX═CN or CF3,D=wherein# is the point of attachment of unit D to the central biphenyl in the structure according to Formula I;Z is a direct bond or is selected from the group consisting of CR3R4, C═CR3R4, C═O, C═NR3, NR3, O, SiR3R4, S, S(O), S(O)2;In each occurrence R1 is the same or different, is H, deuterium, a linear alkyl group having 1 to 5 C atoms, a linear alkenyl or alkynyl group having 2 to 8 C atoms, a branched or cyclic alkyl, alkenyl or alkynyl group having 3 to 10 C atoms, wherein one or more H atoms can be replaced by deuterium or an aromatic having 5 to 15 aromatic ring atoms, which can in each case be substituted with one or more radicals R6;and wherein at least one Ra is not H.