Imidazoazacyclo OLED Material for Light Extraction and Low Voltage
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Solution Overview
Problem
Current organic electroluminescent apparatuses face challenges in enhancing luminous efficiency, reducing driving voltage, and extending service life, primarily due to limitations in the thermal stability, light chemical stability, electrochemical stability, and refractive index of existing light extraction layer materials.
Innovation Solution
The development of an imidazoazacyclo compound with a specific structure, which exhibits low sublimation temperature, good light and electrical stability, high refractive index, and minimal refractive index variation across the visible light spectrum, enabling its application as an electron transmission material, hole barrier layer material, and light extraction layer material in OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light extraction layer materials are used, then the apparatus structure is simple, but the refractive index is low and external quantum efficiency is limited
Solution Approach 1:
The patent changes the molecular structure parameters of the light extraction layer material by introducing imidazoazacyclo core structures with specific substituents (R1-R6 groups), which directly increases the refractive index from conventional values below 1.85 to above 1.90, thereby improving external quantum efficiency without adding structural layers
Solution Approach 2:
The patent creates composite molecular structures by combining imidazoazacyclo core with various aromatic hydrocarbon groups and heterocyclic groups, forming compounds with optimized optical properties that achieve high refractive index while maintaining processability and stability
2Stability of the object's composition
If existing light extraction materials are used, then the material selection is simple, but the refractive index varies hugely across red, green and blue wave bands
Solution Approach 1:
The patent optimizes molecular parameters by selecting specific core structures and substituent groups that provide balanced electron distribution, resulting in refractive indexes across red, green and blue bands that differ by less than 0.05, ensuring consistent optical performance across the visible spectrum
Solution Approach 2:
The patent introduces different substituent groups (R1-R6) at specific positions on the imidazoazacyclo core to locally adjust electron density and polarizability, achieving uniform refractive index characteristics across different wavelength regions through targeted molecular modification
3Duration of action of stationary object
If compounds with improved triplet state energy level are used, then the service life is extended, but the glass-transition temperature and luminous efficiency need further improvement
Solution Approach 1:
The patent combines imidazoazacyclo core with aromatic hydrocarbon groups and heterocyclic groups to create composite molecular structures that simultaneously achieve high triplet state energy levels (improving service life) and high refractive indexes (improving luminous efficiency through enhanced light extraction), resolving the trade-off between durability and efficiency
4Ease of manufacture
If polyphenylenediamine-based light extraction materials are used, then the material is easy to manufacture, but the refractive index is slightly low and red light extraction needs improvement
Solution Approach 1:
The patent modifies the molecular parameters by replacing polyphenylenediamine structures with imidazoazacyclo cores and introducing specific aromatic and heterocyclic substituents, which increases the refractive index particularly in the red light region while maintaining vacuum sublimation deposition compatibility for ease of manufacture
Data Source
AI summary
The present invention relates to an imidazoazacyclo compound and an application thereof. The compound of the present invention has a structure as shown in a formula I. The imidazoazacyclo compound of the present invention has the advantages of low sublimation temperature, good light stability, electrical stability and thermal stability, high refractive index, small difference of refractive index in a visible light area and the like, and an apparatus prepared by the compound has the advantages of low voltage, long service life, high luminous efficiency and the like and can be used in an organic luminescent apparatus. In particular, as an electron transmission material, a hole barrier layer material and a light extraction layer material, the imidazoazacyclo compound has the probability of being applied to an AMOLED industry.