Phenazine Derivative Near-Infrared Organic EL Device
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Solution Overview
Problem
Current near-infrared organic electroluminescent devices face challenges in achieving high efficiency due to unbalanced charge trapping and exciton quenching, with metal complexes being expensive and thermally activated delayed fluorescent materials not yet attaining satisfactory performance.
Innovation Solution
A phenazine derivative with a donor group linked via a 7-conjugated system is used as a light-emitting material, allowing for efficient near-infrared light emission by effectively utilizing triplet exciton energy through delayed fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal complexes (platinum or iridium complexes) are used as room-temperature phosphorescent materials for near-infrared light emission, then external quantum efficiency is improved, but manufacturing cost increases and stable supply becomes difficult
Solution Approach 1:
The patent replaces expensive metal complexes with organic compounds containing only carbon, hydrogen, nitrogen, and other abundant elements. These organic light-emitting materials achieve comparable external quantum efficiency (2.8% at 890 nm) without relying on scarce noble metals, thereby reducing manufacturing cost and ensuring stable supply while maintaining high productivity in near-infrared light emission
Solution Approach 2:
The patent modifies the molecular structure parameters of the light-emitting material by designing specific organic compounds with electron-donating groups (such as amino groups) attached to the phenazine core. This structural parameter change enables the material to exhibit delayed fluorescence with high external quantum efficiency in the near-infrared region, replacing metal complexes without sacrificing performance
2Ease of manufacture
If thermally activated delayed fluorescent materials are used for near-infrared light emission, then manufacturing cost is reduced, but light emission efficiency remains insufficient
Solution Approach 1:
The patent optimizes the molecular structure parameters of thermally activated delayed fluorescent materials by introducing specific electron-donating groups (amino groups, alkoxy groups) at defined positions on the phenazine skeleton. This structural optimization extends the emission wavelength to the near-infrared region (peak at 680-950 nm) while maintaining high external quantum efficiency (up to 2.8% at 890 nm), thereby improving light emission efficiency without increasing manufacturing cost
Solution Approach 2:
The patent creates composite molecular structures by combining the phenazine core (providing rigid backbone and electron-accepting properties) with electron-donating substituent groups. This composite structure achieves both thermal activation for delayed fluorescence and near-infrared emission with high efficiency, overcoming the limitations of previous single-structure materials
3Productivity
If triplet excitons are utilized for light emission in organic light emitting materials, then luminous efficiency is improved, but the complexity of managing triplet exciton dynamics increases
Solution Approach 1:
The patent designs organic light-emitting materials that automatically utilize triplet excitons for light emission through thermally activated delayed fluorescence mechanism. The molecular structure inherently facilitates reverse intersystem crossing from triplet to singlet state, enabling the material to self-manage triplet excitons without requiring complex external control systems or additional device layers, thereby improving luminous efficiency while maintaining device simplicity
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 phenazine derivative-based organic EL device achieves high-efficiency near-infrared light emission by promoting reverse intersystem crossing and reducing energy wastage, leading to improved external quantum efficiency and reduced roll-off phenomena.
Implementation Method 1
the energy difference ΔEST between the excited singlet energy level ES1 and the excited triplet energy level ET1 is small and therefore reverse intersystem crossing from the excited triplet state to the excited singlet state readily occurs
Implementation Method 2
thermally activated delayed fluorescent materials are known... the compound of the present invention includes a compound that emits delayed fluorescence
Implementation Method 3
organic electroluminescent devices (organic EL devices)... an organic light emitting device using the compound of the present invention as a light emitting material may realize high-efficiency near-infrared light emission
Data Source
AI summary
A high-efficiency near-infrared emitting organic EL device may be provided, using a compound represented by the following general formula. At least one of R1 to R4 is *-Ar-D, or R1 and R2, R2 and R3, or R3 and R4 bond to each other to form an aromatic ring having D. D represents a donor group, and Ar represents an arylene group.