Oxygen-Containing Fused Ring Derivative for Organic EL Blocking Layer
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Solution Overview
Problem
Current organic electroluminescence (EL) devices face challenges in achieving high efficiency while preventing an increase in applied voltage, particularly in utilizing the Triplet-Triplet Fusion (TTF) phenomenon effectively.
Innovation Solution
A novel oxygen-containing fused ring derivative is introduced as a material for a blocking layer, which promotes the TTF phenomenon by confining triplet excitons and enhancing the charge transporting properties, thereby improving the luminous efficiency of organic EL devices without increasing the applied voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a blocking layer comprising BCP (bathocuproine) is provided adjacent to the emitting layer to confine triplet excitons, then luminous efficiency is improved, but applied voltage increases
Solution Approach 1:
The patent changes the chemical structure parameters of the blocking layer material by introducing oxygen-containing fused ring structures (formulas 1-5) with specific molecular weights and triplet energy levels. This structural modification allows the material to achieve both efficient triplet exciton confinement and low voltage operation, resolving the contradiction between luminous efficiency improvement and voltage increase
Solution Approach 2:
The patent develops composite blocking layer materials that combine oxygen-containing fused ring structures with specific heterocyclic groups (formulas 2-5). This composite structure integrates the benefits of high triplet energy for exciton confinement with optimized charge transport properties, enabling high efficiency without voltage penalty
2Productivity
If materials with high triplet energy are used in the blocking layer to prevent diffusion of triplet excitons, then efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by designing the blocking layer material with specific functional groups positioned at particular locations in the molecular structure. The oxygen-containing fused ring core (formulas 1-5) provides high triplet energy locally, while the attached heterocyclic groups (formulas 2-5) provide charge transport functionality, achieving both efficiency and simplicity through localized functional differentiation
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 oxygen-containing fused ring derivative effectively confines triplet excitons, leading to increased luminous efficiency and reduced voltage requirements in organic EL devices, making them more efficient and power-efficient.
Implementation Method 1
a material having a high triplet energy is used in a layer which is adjacent to the interface on the cathode side of the emitting layer, whereby a high efficiency is attained
Implementation Method 2
An organic electroluminescence (EL) device is a self-emission device utilizing the principle that a fluorescent compound emits light by the recombination energy of holes injected from an anode and electrons injected from a cathode when an electric field is impressed
Implementation Method 3
emission derived from triplet excitons has recently been reported (for example, Non-Patent Documents 1 and 2, Patent Document 3)
Data Source
AI summary
An oxygen-containing fused ring derivative represented by the following formula (1) wherein Ar1 is an m-valent fused ring group in which four or more rings including one or more rings selected from a furan ring and a pyran ring are fused and HAr is any of the nitrogen-containing heterocyclic group represented by the following formulas (2) to (5):