Solution-Processed OLED Layers with TADF and Platinum Emitters
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Solution Overview
Problem
Existing organic electroluminescent devices face challenges in achieving high efficiency, narrow emission spectrum, and long device lifetime, particularly in blue phosphorescent devices, and the preparation of multiple compound layers through evaporation methods is costly and complex.
Innovation Solution
An organic electroluminescent device with a light-emitting layer prepared through a solution method, comprising a first organic layer with a polymer and a light-emitting layer containing a first host compound, a second host compound, a platinum metal complex, and a thermally activated delayed fluorescence compound, which improves device efficiency and maintains a narrow full width at half maximum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum thermal evaporation method is used to fabricate small molecule OLEDs, then device performance can be achieved, but manufacturing cost and process complexity increase significantly
Solution Approach 1:
The patent replaces the vacuum thermal evaporation method (physical vapor deposition) with a solution processing method. The light-emitting layer is prepared by dissolving host compounds, phosphorescent emitters, and TADF materials in a solvent to form an ink, which is then coated onto the substrate using conventional printing or coating techniques. This substitution eliminates the need for complex vacuum equipment and multi-source evaporators, significantly simplifying the fabrication process while maintaining device performance.
Solution Approach 2:
The patent changes the fabrication parameters from high-vacuum, high-temperature evaporation conditions to ambient or mild conditions suitable for solution processing. By controlling solvent selection, coating conditions, and thermal treatment parameters, the patent achieves comparable device performance with a much simpler manufacturing process that can be scaled industrially.
2Reliability
If multiple evaporation sources are used to prepare light-emitting layer with multiple compounds, then emission performance is achieved, but industrial cost increases significantly
Solution Approach 1:
The patent merges multiple compounds (host compounds, phosphorescent emitters, and TADF materials) into a single solution-based light-emitting layer. Instead of using multiple evaporation sources to deposit separate layers, all components are dissolved in a common solvent and coated together in one step. This merging approach maintains the desired emission performance while dramatically reducing manufacturing complexity and cost.
Solution Approach 2:
The patent creates a universal solution processing method that can accommodate multiple different compounds and emission mechanisms (phosphorescence and TADF) within a single coating process. The solution-based approach provides a universal platform that eliminates the need for specialized multi-source evaporation equipment, making the process suitable for industrial scaling.
3Reliability
If evaporation method is used to prepare organic functional layer, then layer formation is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent replaces energy-intensive vacuum thermal evaporation with low-energy solution coating techniques. The organic functional layers are formed by coating solutions containing dissolved or dispersed materials onto substrates using methods such as spin coating, dip coating, or inkjet printing, followed by mild thermal treatment to remove solvent and form the final layer. This substitution reduces energy consumption by orders of magnitude while achieving comparable layer formation quality.
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 method reduces costs and simplifies the process while significantly enhancing device efficiency and maintaining excellent performance, offering a broad application prospect for organic electroluminescent devices.
Implementation Method 1
In the TADF device, the triplet excitons can go through reverse intersystem crossing to generate singlet excitons, resulting in high IQE
Implementation Method 2
phosphorescent OLED, which uses triplet emission from heavy metal containing complexes as the emitter
Implementation Method 3
the light-emitting layer is prepared through a solution method
Data Source
AI summary
Provided are an organic electroluminescent device, a display device and an organic light-emitting ink. The organic electroluminescent device comprises a thermally activated delayed fluorescence compound represented by a structure of Formula 1. The organic electroluminescent device of the present disclosure not only has the advantages of a low cost and a simple process but also can maintain a relatively narrow full width at half maximum and significantly improve device efficiency compared with a normal thermally activated delayed fluorescence (TADF) device without a platinum metal complex as a phosphorescence sensitizer, thereby exhibiting very excellent device performance. Therefore, the organic electroluminescent device has a broad application prospect. Further provided are a display device comprising the organic electroluminescent device, and an organic light-emitting ink.