Dual Emitting Layer OLED Structure for Higher Luminous Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic electroluminescence devices face challenges in enhancing performance, particularly in terms of luminous efficiency and overall device performance.
Innovation Solution
The device incorporates a dual emitting layer structure with specific host materials in each layer, where the first emitting layer contains a first compound with a defined group represented by formula (1) and the second emitting layer contains a second compound with a defined group represented by formula (2), with both layers in direct contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single emitting layer is used in the organic EL device, then the device structure is simple, but the luminous efficiency is limited due to the 25%:75% singlet:triplet exciton generation ratio
Solution Approach 1:
The emitting layer is divided into two distinct layers: a first emitting layer containing a first host material and a second emitting layer containing a second host material. This segmentation allows each layer to be optimized for different exciton types, with the first layer handling singlet excitons and the second layer handling triplet excitons, thereby resolving the efficiency limitation while maintaining structural clarity.
Solution Approach 2:
Different host materials are selected for different regions (layers) of the emitting structure. The first host material in the first emitting layer is specifically chosen to efficiently manage singlet excitons, while the second host material in the second emitting layer is optimized for triplet excitons. This local optimization of material properties according to the specific exciton type in each region enables overall efficiency improvement.
2Ease of manufacture
If conventional host materials are used in the organic EL device, then the manufacturing process is straightforward, but the overall device performance is insufficient
Solution Approach 1:
The invention changes the chemical structure parameters of the host materials by introducing specific structural features (formula (1) with substituents R1-R6 and formula (2) with substituents R7-R12). These parameter changes in molecular structure lead to improved device performance including enhanced luminous efficiency and stability, while the manufacturing process remains straightforward as the compounds can be synthesized using conventional organic synthesis methods.
Solution Approach 2:
The device employs composite material strategies by combining specifically designed host materials (with defined structural formulas and substituent groups) with other functional materials in the emitting layers. This composite approach, where host materials are carefully selected and combined with dopants and other components, achieves superior device performance while maintaining ease of manufacture through conventional layer-by-layer fabrication processes.
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 enhances the luminous efficiency and overall performance of the organic electroluminescence device.
Implementation Method 1
When a voltage is applied to an organic EL device, holes and electrons are injected from an anode and a cathode, respectively, into an emitting layer. The injected holes and electrons are recombined in the emitting layer to form excitons.
Data Source
AI summary
An organic electroluminescence device includes: an anode; a cathode; a first emitting layer; and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer contains, as a first host material, a first compound that has at least one group represented by a formula (11A) below and that is represented by a formula (1) below, the second emitting layer contains, as a second host material, a second compound represented by a formula (2) below, and the first emitting layer and the second emitting layer are in direct contact with each other.