Organic Compound Triphenylene Skeleton Enhances OLED Efficiency
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Solution Overview
Problem
Current organic light-emitting elements face challenges in achieving high light emission efficiency and durability, particularly in green phosphorescent elements, where the triplet excited state of the host molecule is lower than that of the guest molecule, leading to reduced energy transfer efficiency and durability.
Innovation Solution
An organic compound with a triphenylene skeleton and a nitrogen-containing chalcogen heterocyclic skeleton is developed, where the unit A has a lower triplet excited state than unit B, ensuring high T1 energy transfer efficiency and durability by localizing excitation energy and minimizing bond dissociation, with a nitrogen-carbon-chalcogen atom skeleton to enhance intermolecular interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional organic compound is used in green phosphorescent elements, then the element can operate, but the triplet excited state energy of the host molecule is lower than that of the guest molecule, resulting in reduced energy transfer efficiency and durability
Solution Approach 1:
The patent modifies the molecular structure of the organic compound by introducing a nitrogen-containing chalcogen heterocyclic skeleton (units B and B') with high triplet excited state energy (T1 > 2.85 eV) connected to a triphenylene core (unit A). This structural parameter change ensures the host molecule has higher T1 energy than the guest molecule, resolving the energy transfer efficiency problem while improving durability through enhanced thermal stability and intermolecular interactions.
Solution Approach 2:
The patent creates a composite molecular structure combining unit A (triphenylene skeleton) with units B and B' (nitrogen-containing chalcogen heterocyclic skeletons). This composite structure integrates the benefits of rigid aromatic cores with high-energy heterocyclic units, achieving both high T1 energy for efficient energy transfer and structural stability for improved durability.
2Productivity
If the triplet excited state energy is not optimized, then the structure can be simpler, but the energy transfer efficiency and operational lifetime are reduced
Solution Approach 1:
The patent applies local quality by concentrating the high T1 energy function in specific units (B and B' with nitrogen-containing chalcogen heterocyclic skeletons) while maintaining a simple triphenylene core (unit A). This localized functional design achieves high energy transfer efficiency without requiring complex overall molecular structures, balancing productivity and structural simplicity.
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 organic compound significantly enhances the external quantum efficiency and durability of organic light-emitting elements by maintaining high energy transfer efficiency and thermal stability, leading to longer-lasting and more efficient light emission.
Implementation Method 1
the unit A has a lower triplet excited state than unit B, ensuring high T1 energy transfer efficiency
Implementation Method 2
Electrons and holes are injected from the pair of electrodes to generate an exciton of a light-emitting organic compound in the organic compound layer. When the exciton returns to its ground state, the organic light-emitting element emits light.
Data Source
AI summary
An organic compound represented by [1], satisfying (i) and (ii), and represented by [2-1] or [2-2].A-(B)m  [1](i) T1 of the unit A<T1 of the unit B, and(ii) HOMO-LUMO orbitals responsible for T1 transition are present in the unit A,wherein R1 is selected from alkyl groups and the like, m denotes an integer of 1 or more and 5 or less, and n denotes an integer of 0 or more and 4 or less, the unit B is a fused ring with a partial structure represented by the general formula [3-1] or [3-2] or the like and is bonded to the unit A via a carbon atom, wherein X is selected from an oxygen atom, a sulfur atom, and the like, and the rings C to E independently denote a single ring and may have a deuterium atom or an alkyl group.