Organic Light Emitting Device Charge Generation Layer
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Solution Overview
Problem
Conventional tandem organic light emitting devices face issues with electron or hole transport between stacks due to poor interface properties, leading to increased driving voltage and decreased efficiency, which affects the lifespan of the device.
Innovation Solution
An organic light emitting device is designed with a charge generation layer comprising a first organic substance with electron-withdrawing substituents and a second organic substance capable of injecting holes, specifically using compounds represented by Formulae 1 to 3, to improve charge generation and reduce driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional charge generation layer materials (HAT-CN or MoO3) are used, then the device structure is simple, but electron or hole transport between stacks fails due to poor interface properties, leading to increased driving voltage and decreased efficiency
Solution Approach 1:
The patent changes the chemical composition parameters of the charge generation layer by introducing organic compounds with specific electron-withdrawing groups (cyano, nitro, fluorine) and electron-donating groups (tertiary amine). This parameter change optimizes the HOMO/LUMO energy levels to achieve better interface properties with adjacent stacks, enabling effective charge transport while maintaining manufacturing simplicity
Solution Approach 2:
The patent uses composite organic materials combining electron-withdrawing substituents (such as cyano, nitro, or fluorine groups) and electron-donating groups (such as tertiary amine) within the same charge generation layer compound. This composite structure creates optimal energy level alignment at interfaces, resolving the charge transport issue while keeping the layer structure simple
2Device complexity
If conventional charge generation layer materials are used, then the device structure is simple, but driving voltage increases and efficiency decreases due to poor charge transport
Solution Approach 1:
The patent optimizes the energy level parameters (HOMO and LUMO levels) of the charge generation layer by selecting organic compounds with specific substituent groups. This parameter optimization reduces energy barriers at interfaces, enabling efficient charge transport at lower driving voltages without increasing device complexity
Solution Approach 2:
The charge generation layer acts as an intermediary between adjacent light-emitting stacks, mediating charge transfer through optimized molecular structures with electron-withdrawing and electron-donating groups. This intermediary function reduces energy loss and improves efficiency while maintaining simple device architecture
3Device complexity
If conventional charge generation layer materials are used, then the device structure is simple, but device lifespan deteriorates due to poor charge transport and increased driving voltage
Solution Approach 1:
The patent changes the chemical parameters of the charge generation layer to achieve optimal energy level alignment, which reduces operational stress and improves charge transport efficiency. This parameter optimization decreases degradation rates and extends device lifespan while keeping the layer composition relatively simple
Solution Approach 2:
The optimized charge generation layer serves as a protective intermediary that facilitates smooth charge transfer between stacks, reducing interface defects and operational stress. This intermediary function enhances device reliability and extends operational lifetime without complicating the overall device structure
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 effectively stabilizes electron and hole injection between stacks, decreasing driving voltage and enhancing efficiency, thereby extending the lifespan of the tandem organic light emitting device.
Implementation Method 1
This charge generation layer transports electrons or holes to an adjacent stack
Data Source
AI summary
Discussed is an organic light emitting device that exhibits improved efficiency and driving voltage by applying a novel material facilitating charge generation to a charge generation layer. The charge generation layer contains a compound represented by the following formulae:wherein R1, R2, R3, R4, R5, R6, R7 and R8 are optionally substituted and are independently selected from an aromatic group having 6 to 20 carbon atoms, and R9 and R10 are independently selected from hydrogen, an optionally substituted aromatic ring having 6 to 20 carbon atoms and an optionally substituted heterocyclic compound having 3 to 17 carbon atoms and one or more elements of N, S and P.