Organic Light Emitting Device with Segmented Organic Layers
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Solution Overview
Problem
Current organic light emitting devices face challenges in achieving high efficiency and low driving voltage due to limitations in material selection and layer structure, which affect the performance and stability of the light emission process.
Innovation Solution
The organic light emitting device incorporates a specific compound structure, with a first organic material layer between the anode and light emitting layer, a light emitting layer containing another compound, and a second organic material layer between the light emitting layer and cathode, where the compounds in these layers are designed to optimize hole and electron injection and transfer, enhancing the overall efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organic material layers are used in the organic light emitting device, then the device structure is simple, but the light emission efficiency is low and driving voltage is high
Solution Approach 1:
The organic material layer is segmented into three distinct layers: a first organic material layer adjacent to the anode, a light emitting layer in the middle, and a second organic material layer adjacent to the cathode. Each layer uses compounds with specific energy level ranges optimized for its function, allowing independent optimization of hole injection, light emission, and electron injection processes without increasing overall structural complexity
Solution Approach 2:
Each organic material layer is assigned specific local properties through compound selection: the first layer uses compounds with HOMO levels between 5.5-6.5 eV for optimal hole injection from the anode, the light emitting layer uses compounds with HOMO levels between 5.0-6.0 eV for efficient exciton formation and light emission, and the second layer uses compounds with HOMO levels between 4.5-5.5 eV for optimal electron injection from the cathode
2Adaptability or versatility
If conventional organic materials are used, then material selection is limited, but manufacturing process is simpler
Solution Approach 1:
The patent defines specific parameter ranges for HOMO energy levels of compounds in each layer to optimize device performance. By specifying that the first layer compounds have HOMO levels of 5.5-6.5 eV, the light emitting layer compounds have HOMO levels of 5.0-6.0 eV, and the second layer compounds have HOMO levels of 4.5-5.5 eV, the patent enables flexible material selection within these parameter ranges while maintaining manufacturing simplicity through standardized deposition processes
3Power
If energy levels of organic material layers are not optimized, then device structure is simpler to design, but driving voltage remains high and efficiency is low
Solution Approach 1:
The patent optimizes the HOMO energy level parameters of compounds in each organic material layer to achieve proper energy level alignment. The first layer uses compounds with HOMO levels of 5.5-6.5 eV, the light emitting layer uses compounds with HOMO levels of 5.0-6.0 eV, and the second layer uses compounds with HOMO levels of 4.5-5.5 eV. This parameter optimization enables lower driving voltage and higher efficiency without requiring complex device结构设计
Solution Approach 2:
The light emitting layer acts as an intermediary between the first and second organic material layers, with its compound having HOMO levels of 5.0-6.0 eV that are intermediate between the first layer (5.5-6.5 eV) and the second layer (4.5-5.5 eV). This intermediary energy level configuration facilitates smooth charge carrier transport and reduces energy barriers, contributing to lower driving voltage
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 improved light emission efficiency and reduced driving voltage, leading to a more effective and stable organic light emitting device.
Implementation Method 1
Chemical Formula 1 and Chemical Formula 3 satisfy any one or more of the following: |EL1|<|EL3|, Es1>Es3, ET1>ET3 wherein EL1 means a LUMO energy level (eV) of the compound of Chemical Formula 1, EL3 means a LUMO energy level (eV) of the compound of Chemical Formula 3, Es1 means a singlet energy (eV) of the compound of Chemical Formula 1, Es3 means a singlet energy (eV) of the compound of Chemical Formula 3, ET1 means a triplet energy (eV) of the compound of Chemical Formula 1, and ET3 means a triplet energy (eV) of the compound of Chemical Formula 3
Implementation Method 2
An organic light emission phenomenon generally refers to a phenomenon converting electrical energy to light energy using an organic material. When a voltage is applied between the two electrodes in such an organic light emitting device structure, holes and electrons are injected to the organic material layer from the anode and the cathode, respectively, and when the injected holes and electrons meet, excitons are formed, and light emits when these excitons fall back to the ground state
Data Source
AI summary
Provided is an organic light emitting device including an anode; a cathode; a light emitting layer between the anode and the cathode; a first organic material layer between the light emitting layer and the anode; and a second organic material layer between the light emitting layer and the cathode, wherein the first organic material layer comprises a compound of Chemical Formula 1, the light emitting layer comprises a compound of Chemical Formula 2, the second organic material layer comprises a compound of Chemical Formula 3, and Chemical Formula 1 and Chemical Formula 3 satisfy one or more of <Equation 1> to <Equation 3>:|EL1|<EL3| <Equation 1>Es1>Es3 <Equation 2>ET1>ET3 <Equation 3>