EL Element Ionic Liquid Light-Emitting Layer Vacuum Deposition
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Solution Overview
Problem
The application of existing upconversion technologies involving triplet-triplet annihilation to electroluminescent (EL) elements is hindered by the need for wet processes and increased manufacturing steps, making mass production difficult, and the challenge of forming a light-emitting layer with desirable film thickness in EL elements.
Innovation Solution
An EL element is created with a light-emitting layer comprising an ionic liquid, a phosphorescent material, and a fluorescent material, where the fluorescent material and phosphorescent material are homogeneously dispersed in a liquid film, allowing for efficient triplet-triplet annihilation and formed using an in-situ vacuum vapor deposition process, eliminating the need for additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If donors and acceptors are mixed together in a volatile organic solvent to cause energy transfer by utilizing diffusion, then high efficiency triplet-triplet annihilation can be achieved, but it is not easy to apply to EL elements produced by layering organic films in a vacuum
Solution Approach 1:
The patent changes the physical state of the ionic liquid from solid to liquid by controlling temperature, enabling molecular diffusion necessary for TTA while maintaining vacuum deposition compatibility. The ionic liquid serves as both the medium for donor-acceptor mixing and the depositable material in vacuum conditions.
Solution Approach 2:
The ionic liquid acts as an intermediary substance that enables energy transfer between donors and acceptors through its liquid state, facilitating diffusion-based TTA while being compatible with vacuum vapor deposition processes used in EL element manufacturing.
2Stability of the object's composition
If a wet process is used to form the light-emitting layer by dissolving materials in solvent, then homogeneous dispersion can be achieved, but the number of manufacturing processes increases and mass production becomes difficult
Solution Approach 1:
The patent extracts and eliminates the volatile organic solvent from the process, using only ionic liquid which can be directly deposited in vacuum. This removes the need for separate drying and degassing steps while maintaining homogeneous dispersion through vacuum co-deposition of all components.
Solution Approach 2:
The patent combines multiple processes into one vacuum vapor deposition step, simultaneously depositing the ionic liquid, donors, and acceptors in a single operation, thereby eliminating sequential wet processing steps and enabling mass production.
3Loss of energy
If the light conversion element is formed as a liquid, then TTA can occur through molecular diffusion, but it is difficult to form the element to have a film thickness desirable for EL elements
Solution Approach 1:
The patent replaces liquid handling and thickness control mechanisms with vacuum vapor deposition control, where film thickness is precisely controlled by deposition time and rate, eliminating the difficulty of controlling liquid film thickness while maintaining TTA efficiency.
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 enables the production of EL elements with high quantum efficiency for upconversion light emission, facilitating efficient energy transfer and collision of molecules, thus achieving high-efficiency light emission while simplifying the manufacturing process.
Implementation Method 1
upconversion involving triplet-triplet annihilation (TTA: T-T Annihilation)
Implementation Method 2
it is necessary to produce overlaps of the wave functions between acceptor molecules and it is desirable that the distance between acceptor molecules be from 0 nm to 1 nm. Thus, in the field of study of upconversion utilizing TTA, a prevalent method is one in which donors and acceptors are mixed together in a volatile organic solvent to cause energy transfer by utilizing the diffusion of donors and acceptors in the solution
Implementation Method 3
in-situ vacuum vapor deposition process
Data Source
AI summary
Provided is an EL element utilizing upconversion light emission involving highly efficient triplet-triplet annihilation. A blue-light-emitting layer includes an ionic liquid, a red phosphorescent material, and a blue fluorescent material. The blue fluorescent material and the red phosphorescent material are homogeneously dispersed in a liquid film of the ionic liquid.