Benzonaphthofuran Hole-Transport Material for OLED Hole Injection
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Solution Overview
Problem
Current light-emitting elements face challenges in achieving high emission efficiency and long lifetime due to difficulties in hole injection between layers with mismatched energy levels, particularly when the LUMO level of the hole-injection layer is distant from the HOMO level of the hole-transport layer.
Innovation Solution
A hole-transport material with a benzonaphthofuran skeleton and an amine skeleton is used, where the amine skeleton is bonded to the 6- or 8-position of the benzonaphthofuran, facilitating efficient hole transport and improving the HOMO level alignment, thereby enhancing the light-emitting element's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the LUMO level of the hole-injection layer is distanced from the HOMO level of the hole-transport layer, then the organic compound having acceptor property can be easily deposited by evaporation, but hole injection from the hole-injection layer into the hole-transport layer becomes difficult
Solution Approach 1:
A hole-transport layer is introduced as an intermediary between the hole-injection layer and the light-emitting layer. This intermediate layer has a HOMO level that is higher than the LUMO level of the hole-injection layer, creating a stepped energy level structure that facilitates hole injection while maintaining the advantages of the acceptor property material.
Solution Approach 2:
The energy level parameters of the hole-transport layer are specifically designed to bridge the gap between the hole-injection layer and the light-emitting layer. By adjusting the HOMO level of the hole-transport layer to be higher than the LUMO level of the hole-injection layer, the patent creates favorable energy level alignment for hole injection.
2Device complexity
If conventional hole-transport materials are used, then the device structure can be simplified, but the lifetime and emission efficiency of the light-emitting element are limited
Solution Approach 1:
The patent employs composite material strategies by combining the hole-injection layer with acceptor property materials and the hole-transport layer with high HOMO level materials. This composite structure optimizes both the hole injection and hole transport functions, leading to improved element lifetime and emission efficiency.
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 proposed solution results in a light-emitting element with improved hole injection, increased lifetime, and high emission efficiency, suitable for applications in display and lighting devices.
Implementation Method 1
Light-emitting elements (organic EL elements) including organic compounds and utilizing electroluminescence (EL) have been put to more practical use. Carriers are injected by application of voltage to the element, and light emission can be obtained from the light-emitting material by using the recombination energy of the carriers.
Data Source
AI summary
A novel light-emitting element is provided. A light-emitting element with a long lifetime is provided. A light-emitting element with high emission efficiency is provided. A novel organic compound is provided. A novel organic compound having a hole-transport property is provided. A novel hole-transport material is provided. A hole-transport material including an organic compound having a substituted or unsubstituted benzonaphthofuran skeleton and a substituted or unsubstituted amine skeleton is provided. A light-emitting element using the hole-transport material is provided. An organic compound in which an amine skeleton including two aromatic hydrocarbon groups having 6 to 60 carbon atoms is bonded to the 6- or 8-position of the benzonaphthofuran skeleton is provided.