OLED Hole Injection Layer Composition for Lower Voltage Operation
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Solution Overview
Problem
Existing organic electronic devices, such as OLEDs, face challenges in achieving balanced hole and electron injection, leading to suboptimal operating voltage, efficiency, and lifetime, particularly due to the performance limitations of the hole injection layer.
Innovation Solution
Incorporating a compound of Formula (1) as a semiconductor layer, specifically a hole injection layer, with a calculated HOMO level of 6.5 eV, which is further away from the vacuum level, and a covalent matrix compound, enabling improved hole injection and electron transport, suitable for vacuum thermal evaporation and mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional hole injection layers are used, then device structure is simple, but operating voltage is high and efficiency is poor
Solution Approach 1:
The patent employs composite materials by combining a sulfonimide metal complex (Formula 1) with a covalent matrix compound to form a semiconductor layer. This composite structure enables improved hole injection and electron transport characteristics, achieving lower operating voltage and higher efficiency without significantly complicating the overall device architecture.
Solution Approach 2:
The invention changes key material parameters by selecting a sulfonimide metal complex with specific HOMO level (6.5 eV) and LUMO level characteristics. This parameter optimization enables balanced charge injection and transport, resolving the contradiction between simple structure and high performance.
2Reliability
If hole injection layer uses conventional materials, then manufacturing is easy, but hole injection capability is insufficient
Solution Approach 1:
The patent optimizes the HOMO level parameter of the hole injection material to 6.5 eV, which provides sufficient hole injection capability. The material is designed to be compatible with vacuum thermal evaporation, maintaining ease of manufacture while achieving superior electrical characteristics.
Solution Approach 2:
The invention replaces conventional solution-based or spin-coating deposition methods with vacuum thermal evaporation, substituting a mechanically simple vapor deposition process. This maintains manufacturing ease while enabling precise control over layer formation and material properties.
3Productivity
If standard semiconductor layers are used, then device structure is simple, but efficiency and lifetime are suboptimal
Solution Approach 1:
The patent creates a composite semiconductor layer combining sulfonimide metal complex and covalent matrix compound. This composite approach enhances both efficiency and lifetime by enabling balanced electron and hole transport, while the layered composite structure remains relatively simple to fabricate.
Solution Approach 2:
The sulfonimide metal complex acts as an intermediary material between the anode and the photoactive layer, facilitating balanced charge transport. This intermediary layer improves overall device efficiency and stability without requiring complex multi-layer structures.
4Adaptability or versatility
If hole injection layer has conventional HOMO level, then material selection is easy, but injection into layers with HOMO further from vacuum level is difficult
Solution Approach 1:
The patent sets the HOMO level at 6.5 eV, a parameter optimized for broad compatibility with various photoactive layers having different HOMO levels. This parameter choice enables the hole injection layer to work effectively with diverse materials while maintaining straightforward manufacturing processes.
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 solution enhances the operating voltage, efficiency, and stability of organic electronic devices by providing superior hole injection capabilities, resulting in improved performance and longevity.
Implementation Method 1
holes injected from the anode move to the EML, via the HTL
Implementation Method 2
electrons injected from the cathode move to the EML, via the ETL
Implementation Method 3
which can be deposited through vacuum thermal evaporation under conditions suitable for mass production
Implementation Method 4
compounds with improved thermal properties
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention is directed to an organic electronic device comprising an anode, a cathode, at least one photoactive layer and at least one semiconductor layer, wherein the at least one semiconductor layer is arranged between the anode and the at least one photoactive layer, and wherein the at least one semiconductor layer comprises a covalent matrix compound or substantially covalent matrix compound, wherein the calculated HOMO of the covalent matrix compound or substantially covalent matrix compound is in the range of < -4.5 eV and > 6.5 eV.