Novel Metal Complexes for High-Efficiency Blue Organic EL Elements
Solution Overview
Problem
Current organic electroluminescent elements face challenges in achieving high external quantum yield and long lifetime, particularly in shortening emission wavelength while maintaining efficiency, and existing production methods like vapor deposition are inefficient for large-area manufacturing.
Innovation Solution
Development of novel metal complexes with specific partial structures that incorporate solubility and film formation controlling groups, allowing for the formation of organic electroluminescent elements with improved quantum yield and longevity, and the use of coating methods for efficient layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional vapor deposition method is used for manufacturing organic EL elements, then element performance can be maintained, but production efficiency is low and it is inefficient for large-area manufacturing
Solution Approach 1:
The patent replaces the conventional vapor deposition method (physical process) with a coating method using solution processing (chemical process). This substitution enables large-area manufacturing and significantly improves production efficiency while maintaining element performance, directly resolving the contradiction between productivity and ease of manufacture.
2Illumination intensity
If emission wavelength is shortened to achieve blue light emission, then display capability is improved, but element lifetime is significantly deteriorated
Solution Approach 1:
The patent changes the chemical parameters of the phosphorescent compound by introducing specific substituents (fluorine atoms, trifluoromethyl groups, cyano groups, picolinic acid ligands, pyrazabole ligands) to adjust the emission wavelength to blue region while simultaneously improving element lifetime. This parameter optimization resolves the contradiction between emission wavelength and element lifetime.
3Loss of energy
If phosphorescent materials with high emission efficiency are used, then quantum efficiency is improved, but emission wavelength shortening and lifetime improvement cannot be achieved simultaneously
Solution Approach 1:
The patent creates composite phosphorescent compounds combining iridium or platinum centers with specifically designed organic ligands (picolinic acid, pyrazabole types) and substituent groups. This composite structure achieves high quantum efficiency while simultaneously enabling blue emission and long lifetime, resolving the contradiction between emission efficiency and the combined requirements of wavelength and lifetime.
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 novel metal complexes enable organic electroluminescent elements with high external quantum yield and long lifetimes, suitable for display devices, and the coating method enhances production efficiency for large-area elements.
Implementation Method 1
utilization of phosphorescence from an excited triplet has been reported... Since the upper limit of internal quantum efficiency becomes 100% by utilization of an excited triplet
Implementation Method 2
An organic electroluminescent element (organic EL element) is an element having a light emission layer placed between a cathode and an anode, in which electrons and positive holes are injected into the light emission layer and excitons are generated by recombination of them, and fluorescence or phosphorescence light is emitted on the occasion of quenching of the excitons
Data Source
AI summary
Provided are a novel compound, an organic EL element which contains such novel compound and has a high external extraction quantum efficiency and a long service life, an illuminating apparatus and a display apparatus.