OLED Organic Semiconductor Layer Voltage and Efficiency
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Solution Overview
Problem
Existing organic light emitting diodes (OLEDs) face issues with high operating voltage and low efficiency, along with organic semiconductor materials having low glass transition temperature and volatility, which affect their performance and manufacturing processes.
Innovation Solution
Incorporating an organic semiconductor layer with an alkali organic complex and a compound of formula 1, specifically designed to improve the OLED's operating voltage, efficiency, glass transition temperature, and volatility, where the compound features a phenyl moiety, anthracenylene, and biphenylene groups, and is preferably non-emissive with a dipole moment between 2.5 and 10 Debye, enhancing the device's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional organic semiconductor materials are used in OLEDs, then the device structure is simple, but the operating voltage is high and efficiency is low
Solution Approach 1:
The patent employs composite organic semiconductor materials comprising multiple components with specific molecular structures (compounds of formulas 1-4) that work synergistically to reduce operating voltage and enhance efficiency. The composite approach allows combining materials with complementary properties: compound 1 provides electron transport capability, compound 2 enhances stability, compound 3 improves charge injection, and compound 4 optimizes energy levels, collectively resolving the contradiction between simple structure and high performance
Solution Approach 2:
The patent systematically optimizes molecular parameters of the organic semiconductor materials, including dipole moments (2.5-10 Debye), HOMO/LUMO energy levels, and glass transition temperatures (above 100°C). By adjusting these parameters through molecular design with specific substituents (aryl groups, heteroaryl groups, alkyl groups), the material properties are tuned to achieve lower operating voltage and higher efficiency without compromising structural simplicity
2Temperature
If conventional organic semiconductor materials are used, then manufacturing is easier, but glass transition temperature is low and volatility is poor
Solution Approach 1:
The patent achieves high glass transition temperatures (above 100°C, preferably above 150°C) by designing rigid molecular backbones with aromatic groups (phenyl, naphthyl, anthryl) and strategic substitution patterns. The molecular structures of compounds 1-4 incorporate stiffening elements that elevate Tg while maintaining appropriate volatility for vacuum deposition, resolving the contradiction between thermal stability and manufacturability
Solution Approach 2:
The patent introduces specific functional groups and substituents at strategic positions within the molecular structures to locally enhance thermal properties without affecting overall volatility. For example, adding bulky aryl groups at terminal positions increases Tg locally, while the core structure maintains planarity and conjugation for adequate vapor pressure, enabling both high temperature stability and ease of deposition
3Productivity
If the organic semiconductor layer uses simple materials, then deposition is easier, but external quantum efficiency is low
Solution Approach 1:
The patent utilizes composite organic semiconductor layers with multiple compounds (formulas 1-4) that collectively enhance external quantum efficiency through complementary mechanisms: compound 1 provides efficient electron transport, compound 2 improves hole blocking, compound 3 enhances charge injection, and compound 4 optimizes energy level alignment. This composite approach achieves high EQE while maintaining relatively simple deposition processes
Solution Approach 2:
The patent optimizes energy level parameters (HOMO/LUMO levels, electron affinity, ionization potential) of the organic semiconductor materials to match with electrode work functions and emission layer energy levels. By tuning these parameters through molecular design, the materials achieve better charge injection and transport efficiency, directly improving external quantum efficiency without requiring complex device structures
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 significantly reduces operating voltage, increases external quantum efficiency, and maintains high glass transition temperature, making the OLEDs more efficient and suitable for manufacturing, with the biphenylene group attachment providing a beneficial effect on performance.
Implementation Method 1
When a voltage is applied to the anode electrode and the cathode electrode, holes injected from the anode electrode move to the EML, via the HIL and HTL, and electrons injected from the cathode electrode move to the EML, via the ETL. The holes and electrons recombine in the EML to generate excitons.
Data Source
AI summary
The invention relates to an Organic light emitting diode comprising an anode electrode, a cathode electrode, at least one emission layer and an organic semiconductor layer, wherein the organic semiconductor layer is arranged between the anode electrode and the cathode electrode and the organic semiconductor layer comprises an alkali organic complex and a compound of formula 1 wherein X is selected from O, S or Se; and R1 and R2 are independently selected from the group consisting of C6 to C18 aryl group and C5 to C18 heteroaryl group, wherein each of R1 and R2 may independently be unsubstituted or substituted with at least one C1 to C12 alkyl group or C1 to C12 alkoxy group, preferably C1 to C4 alkyl group or C1 to C4 alkoxy group; and each R3, R4, R5, and R6 are independently selected from the group consisting of H, C1 to C12 alkyl group or C1 to C12 alkoxy group, preferably H, C1 to C4 alkyl group or C1 to C4 alkoxy group; a method for preparing the same and the compound of Formula 1 comprised therein.