Organic EL Charge Generation Layer for Efficiency and Durable Life
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Solution Overview
Problem
Existing organic EL elements face challenges in achieving both high luminous efficiency and durable life, as recent advancements have increased the requirements for both characteristics.
Innovation Solution
The organic EL element incorporates a charge generation layer composed of an n-type charge generation layer containing a phenanthroline derivative with specific substituents and a p-type charge generation layer with a radialene or indacene derivative, along with electron and hole transporting layers, to enhance luminous efficiency and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional charge generation layers using phenanthroline derivatives with terpyridine/pyrene/dibenzofuran skeletons are used, then luminous efficiency is enhanced, but durable life is insufficient
Solution Approach 1:
The patent modifies the molecular structure of phenanthroline derivatives by changing parameters such as introducing dibenzofuran skeletons with specific substitution patterns (Formula 1) and radialene/indacene derivatives (Formula 2), thereby altering charge generation characteristics to simultaneously improve luminous efficiency and durable life
Solution Approach 2:
The patent employs composite charge generation layers combining n-type charge generation layers with phenanthroline derivatives and p-type charge generation layers with radialene or indacene derivatives, creating a synergistic effect that achieves both high luminous efficiency and extended durable life
2Power
If charge generation layers with optimized luminous efficiency are implemented, then driving voltage is reduced, but film stability deteriorates
Solution Approach 1:
The patent introduces local structural features such as dibenzofuran skeletons with specific substitution patterns at defined positions, creating localized regions of enhanced stability within the charge generation layer that prevent film degradation while maintaining low driving voltage
Solution Approach 2:
Instead of optimizing for low driving voltage first and accepting poor film stability, the patent inverts the approach by incorporating structurally stable dibenzofuran and radialene/indacene frameworks that inherently provide both low driving voltage and high film stability simultaneously
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
This configuration results in an organic EL element with improved luminous efficiency and extended lifespan by optimizing charge generation and transport, reducing driving voltage, and enhancing film stability.
Implementation Method 1
a charge generation layer sandwiched between the light-emitting units, wherein the charge generation layer includes an n-type charge generation layer located on the anode side and a p-type charge generation layer located on the cathode side
Implementation Method 2
an electron transporting layer, and an emissive layer; and a charge generation layer sandwiched between the light-emitting units
Implementation Method 3
a p-type charge generation layer located on the cathode side
Implementation Method 4
a hole transporting layer
Implementation Method 5
organic EL elements (organic electroluminescent elements) have been steadily put into practical use
Data Source
AI summary
An organic EL element is provided which has excellent luminous efficiency and durability life and which comprises: a positive electrode; a negative electrode; two or more light emitting units which are held between the positive electrode and the negative electrode, where each comprises a hole transport layer, an electron transport layer and a light emitting layer; and a charge generation layer, where the charge generation layer is composed of an n-type charge generation layer and a p-type charge generation layer, where the n-type charge generation layer contains a compound represented by general formula (1) and the p-type charge generation layer contains either a compound represented by general formula (2) or a compound represented by general formula (4)where X1 to X3, L1, L2, A, n, A1 to A3, *, Ar, R21, R41 to R46, Z41 and Z42 are as defined.