Organic Light-Emitting Device Electron Injection Layer
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Solution Overview
Problem
Current organic light emitting devices face challenges in achieving high light emission efficiency and long lifetime due to limitations in electron injection and film quality.
Innovation Solution
Incorporating Compound (A), which includes a heteroatom and a cyano group, into the organic material layer between the cathode and the light emitting layer, satisfying specific dipole moment and electron affinity equations, enhances electron injection and film quality, leading to improved light emission efficiency and extended device lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic materials are used in the organic material layer, then the device structure is simple, but the film quality is poor and electron injection is insufficient, leading to low light emission efficiency and short lifetime
Solution Approach 1:
The patent introduces Compound (A) with specific molecular parameters (dipole moment μ and electron affinity EA) that satisfy defined equations. By changing the molecular parameters of the organic material layer through selective compound design, the patent achieves improved film quality and electron injection performance, resolving the contradiction between device lifetime and structural complexity
Solution Approach 2:
The patent employs a composite organic material layer containing Compound (A) combined with other organic materials. This composite structure leverages the unique properties of Compound (A) - particularly its heteroatom and cyano group configuration - to enhance overall film quality and electron injection capability while maintaining device functionality
2Productivity
If electron injection is enhanced to improve light emission efficiency, then more electrons are injected to the light emitting layer, but excessive electron injection causes device degradation and reduces lifetime
Solution Approach 1:
The patent utilizes the specific electron affinity (EA) parameter of Compound (A) to control electron injection. By satisfying the equation EA(Compound A) > EA(other organic materials), the patent achieves optimized electron injection that improves light emission efficiency while preventing excessive electron flow that would degrade the device
Solution Approach 2:
Compound (A) acts as an intermediary layer between the cathode and the light emitting layer. It mediates electron injection by controlling the electron flow through its specific electronic properties, allowing sufficient electrons to reach the light emitting layer for high efficiency while preventing excessive injection that would cause device degradation
3Manufacturing precision
If the dipole moment of the organic material is increased to improve molecular arrangement and film quality, then the film quality improves, but the electron affinity changes and may affect electron injection
Solution Approach 1:
The patent simultaneously optimizes two critical parameters of Compound (A): dipole moment (μ) and electron affinity (EA). By satisfying both equations - μ(Compound A) > μ(other organic materials) for film quality and EA(Compound A) > EA(other organic materials) for electron injection - the patent resolves the contradiction between these two parameters
Solution Approach 2:
The patent designs Compound (A) as a composite molecular structure containing both heteroatoms and cyano groups. This composite structure inherently provides both the high dipole moment needed for molecular arrangement and film quality, and the appropriate electron affinity for effective electron injection, resolving the parameter trade-off
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 use of Compound (A) results in low driving voltage, high light emission efficiency, and a longer lifetime for the organic light emitting device by optimizing electron injection and film quality, while preventing excessive electron injection into the light emitting layer.
Implementation Method 1
Compound (A) has a greatly increased dipole moment by including a heteroatom and a cyano group, and therefore, when an organic material layer including the same forms a film, molecular arrangements more favorably occur by the influence of the dipole moment
Implementation Method 2
when a voltage is applied between the two electrodes, electrons and holes are injected to the organic material layer from the cathode and the anode, respectively
Implementation Method 3
Compound (A) satisfies the following Equation 1 and the following Equation 2: |Ea A|>|Ea El|
Implementation Method 4
The holes and the electrons injected to the organic material layer recombine to form excitons, and light emits when these excitons fall back to the ground state
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present specification relates to an organic light emitting device including a cathode; an anode provided opposite to the cathode; a light emitting layer provided between the cathode and the anode; and an organic material layer provided between the cathode and the light emitting layer, and including Compound (A) including a heteroatom and a cyano group, wherein Compound (A) satisfies Equation 1 and Equation 2.