Organic EL Emitting Layer Ratio for Low-Voltage High Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic electroluminescence devices face challenges in achieving low drive voltage and high luminous efficiency, with existing studies focusing on layering emitting layers but not addressing the ratio and materials of these layers effectively.
Innovation Solution
The device incorporates a specific ratio of film thicknesses in two emitting layers with different host materials and luminescent compounds, using a compound represented by formulas (1), (1A), (1B), or (1C) to enhance efficiency and reduce drive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple emitting layers are layered to enhance device performance, then luminous efficiency is improved, but drive voltage increases
Solution Approach 1:
The patent applies parameter changes by optimizing the film thickness ratio of the first emitting layer to the second emitting layer within a specific range (2/3 to 3/2). This controlled parameter adjustment allows the device to achieve high luminous efficiency while maintaining low drive voltage, resolving the contradiction between improved energy efficiency and increased voltage requirements
Solution Approach 2:
The patent uses composite materials by combining different host materials (first host material and second host material) in the emitting layers. This composite structure enables the device to achieve both high luminous efficiency and low drive voltage by leveraging the complementary properties of different materials working together
2Loss of energy
If multiple emitting layers are layered to enhance device performance, then luminous efficiency is improved, but device complexity increases
Solution Approach 1:
The patent simplifies the multilayer structure by controlling the film thickness ratio parameter within a specific range (2/3 to 3/2). This parameter optimization reduces the need for complex thickness adjustments while maintaining high luminous efficiency, thereby reducing device complexity
Solution Approach 2:
The patent applies local quality by assigning specific functional roles to different emitting layers with distinct host materials. The first emitting layer and second emitting layer have differentiated compositions but work together in a simplified configuration, achieving high efficiency without excessive structural complexity
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 solution results in an organic electroluminescence device with improved luminous efficiency and reduced drive voltage, achieving better performance metrics.
Implementation Method 1
An organic electroluminescence device has found its application in a full-color display for mobile phones, televisions, and the like. When voltage is applied to an organic EL device, holes are injected from an anode and electrons are injected from a cathode into an emitting layer. The injected holes and electrons are recombined in the emitting layer to form excitons.
Implementation Method 2
in order to enhance the performance of the organic EL device, Patent Literature 3 describes a phenomenon in which a singlet exciton is generated by collision and fusion of two triplet excitons (hereinafter, occasionally referred to as a Triplet-Triplet Fusion (TTF) phenomenon).
Data Source
AI summary
An organic electroluminescence device includes an emitting region provided between an anode and a cathode, in which the emitting region includes a first emitting layer and a second emitting layer, a ratio DEM1/DEM2 of a film thickness DEM1 of the first emitting layer to a film thickness DEM2 of the second emitting layer is in a range from 2/3 to 3/2, the first emitting layer contains a first host material and a first luminescent compound, the second emitting layer contains a second host material and a second luminescent compound, and the first host material is a compound represented by a formula (1) below having a group represented by a formula (10).