Phenylether Organic Molecules for OLED TADF Efficiency
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Solution Overview
Problem
Current OLED technologies face limitations in converting excitons into light efficiently due to the use of expensive transition metal complexes and stability issues, while also seeking to exploit delayed fluorescence for improved performance.
Innovation Solution
Development of purely organic molecules with specific structures that facilitate thermally activated delayed fluorescence (TADF) by using chemical units with controlled frontier orbital energies and a separator to interrupt electronic communication, enabling efficient charge-transfer transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transition metal complex compounds are used to achieve high light conversion efficiency, then all excitons can be converted into light, but the cost increases significantly and stability becomes disadvantageous
Solution Approach 1:
The patent replaces expensive transition metal complexes with purely organic molecules that have shorter lifetimes but sufficient stability for device operation. The organic emitters achieve adequate longevity for commercial OLED applications while eliminating the high costs and stability issues associated with precious metal complexes like iridium and platinum.
Solution Approach 2:
The patent modifies molecular parameters by designing organic compounds with specific HOMO-LUMO energy gaps and frontier orbital energy differences greater than 0.8 eV. These parameter changes enable the organic molecules to achieve high light conversion efficiency through thermally activated delayed fluorescence without requiring transition metals.
2Productivity
If transition metal complex compounds are used to achieve high light conversion efficiency, then all excitons can be converted into light, but the cost increases significantly
Solution Approach 1:
The patent replaces expensive transition metal complexes with purely organic molecules that have shorter lifetimes but sufficient stability for device operation. The organic emitters achieve adequate longevity for commercial OLED applications while eliminating the high costs and stability issues associated with precious metal complexes like iridium and platinum.
Solution Approach 2:
The patent creates organic molecule structures that replicate the light-emitting function of transition metal complexes without using the expensive metals. The organic compounds copy the essential photophysical properties needed for high efficiency OLED operation while being much cheaper to manufacture.
3Reliability
If purely organic molecules are used to exploit delayed fluorescence, then costs are reduced and stability improved, but light conversion efficiency decreases to maximum 25%
Solution Approach 1:
The patent modifies molecular parameters by designing organic compounds with specific HOMO-LUMO energy gaps and frontier orbital energy differences greater than 0.8 eV. These parameter changes enable the organic molecules to achieve high light conversion efficiency through thermally activated delayed fluorescence without requiring transition metals.
Solution Approach 2:
The patent exploits dynamic thermal processes to activate delayed fluorescence in organic molecules. The molecules undergo thermally activated transitions from triplet to singlet states, dynamically converting non-emissive excitons into light-emitting states without requiring precious metal complexes.
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 achieves efficient light emission with improved stability and reduced costs, enhancing the service life and efficiency of OLED devices.
Implementation Method 1
A new generation of OLEDs is based on the exploitation of delayed fluorescence (TADF: thermally activated delayed fluorescence or singlet harvesting). Here, for example, Cu(I) complexes can be used, which thermally transform triplet exitons into a singlet state due to a small energy difference between the lowest triplet state T 1 and the singlet state S 1 above it (ΔE(S 1 -T 1 ).
Implementation Method 2
In this layer, negative charge carriers (electrons) and positive charge carriers (holes) meet, which recombine to form so-called excitons (= excited states). The energy contained in the excitons can be emitted by the corresponding emitters in the form of light, in which case this is referred to as electroluminescence.
Data Source
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AI summary
The invention relates to organic molecules, in particular for use in optoelectronic components, such as OLEDs. According to the invention, the organic molecule has a structure of the formula 1, in which E is selected from the group consisting of S, S(=O), S(=O)2, O, C(=O), CR*2 Si(R4)2, Ge(R4)2, NR2, PR3, P(=O)R7, P(=S)R7, AsR3, As(=O)R7, As(=S)R7, SbR3, and BR3; J is not a bond such that a group R* is then present on the two phenyl rings at this position or is a single bond; and AF1 and AF2 are organic chemical units. In each case, R* is independently selected from the group consisting of H, deuterium, phenyl, naphthyl, F, Cl, Br, I, N(R2)2, -CN, -NC, -SCN, -CF3, -NO2, -OH, C(=O)OH, C(=O)OR3, C(=O)N(R3)2, C(=O)SR3, C(=S)SR3, Si(R4)3, B(OR5)2, B(N(R6)2)2, C(=O)R3, P(=O)(R7)2, As(=O)(R7)2, P(=S)(R7)2, As(=S)(R7)2, S(=O)R3, S=NR3, S(=O)NR3, S(=O)2NR3, S(=O)2R3, O-S(=O)2R3, SF5, a linear alkyl, alkoxy, or thioalkoxy group with 1 to 40 C atoms or a linear alkenyl or alkinyl group with 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkinyl, alkoxy, or thioalkoxy group with 3 to 40 C atoms, each group being substitutable with one or more groups R9, wherein one or more adjacent CH2- groups can be replaced with –R9C=CR9-, -C≡C-, or an adjacent CH2- group can be replaced with -Si(R4)2-, -Ge(R4)2-, -Sn(R4)2-, -C(=O)-, -C(=S)-, - C(=Se)-, -C=N-, -C(=O)O-, -C(=O)N(R3)-, -P(=O)(R7)-, -As(=O)(R7)-, -P(=S)(R7)-, - As(=S)(R7)-, -S(=O)-, -S(=O)2-, -NR2-, -O-, or -S-, and one or more H atoms can be replaced with deuterium, F, Cl, Br, I, CN, CF3, or NO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, each system being substitutable with one or more groups R2.