Anthracene Derivative for Low-Voltage Organic EL Devices
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Solution Overview
Problem
Conventional organic electroluminescence (EL) devices have high driving voltage and low luminous efficiency, leading to limited practical applications and a need for further improvements in luminous efficiency and durability.
Innovation Solution
An anthracene derivative with specific substituents and bonding positions is used to enhance intermolecular packing and electron-injecting/transporting performance, allowing for a low-voltage and high-efficient organic EL device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional organic EL emitting materials are used, then the device can be manufactured with existing technology, but the driving voltage is high and luminous efficiency is low
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of emitting materials through specific substituent groups (dibenzofuran, naphthobenzofuran, naphthobenzothiophene) attached to the anthracene core. This structural parameter change optimizes electron-injecting and transporting performance, enabling low-voltage operation while achieving high luminous efficiency exceeding 25 cd/A
Solution Approach 2:
The patent employs composite materials by combining anthracene derivatives with specific substituent groups (dibenzofuran, naphthobenzofuran, or naphthobenzothiophene) to create hybrid emitting materials. These composite structures integrate the benefits of electron injection from dibenzofuran and enhanced luminescence from naphthobenzofuran/naphthobenzothiophene, resolving the contradiction between driving voltage and luminous efficiency
2Reliability
If conventional organic EL materials are used, then device structure is simple, but luminous efficiency is low and durability is poor
Solution Approach 1:
The patent changes molecular parameters by introducing specific substituent groups that enhance both stability and efficiency. The naphthobenzofuran and naphthobenzothiophene groups provide improved molecular stability and resistance to deterioration, while maintaining high luminous efficiency through optimized electron-injecting and transporting properties
Solution Approach 2:
The patent replaces conventional emitting materials with anthracene derivatives that have extended operational lifetimes. The improved durability allows the device to maintain performance over extended periods, effectively replacing shorter-lived conventional materials without requiring complex device architecture
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 anthracene derivative enables organic EL devices to operate at lower voltages while maintaining or exceeding the luminous efficiency of previous materials, improving overall performance and durability.
Implementation Method 1
When an electrical field is applied between the both electrodes, electrons are injected from the cathode and holes are injected from the anode. Further, these electrons are re-combined with the holes in the emitting layer, create an excited state, and energy is emitted as light when the excited state is returned to the ground state.
Data Source
AI summary
An anthracene derivative represented by the following formula (1): wherein in the formula (1), L1 is selected from a single bond and a linking group, and the linking group is selected from a divalent arylene group, a divalent heterocyclic group, and a group formed by linking of 2 to 4 of divalent arylene groups and/or divalent heterocyclic groups. Ar1 is selected from the following formulas (2) and (3). In the formulas (2) and (3), X is selected from an oxygen atom and a sulfur atom. In the formula (2), any one of R11 to R14 is used for bonding to L1. In the formula (3), any one of R21 to R24 is used for bonding to L1. Ar2 is selected from a substituted or unsubstituted aryl group including 6 to 50 ring carbon atoms and a substituted or unsubstituted heterocyclic group including 5 to 50 ring atoms.