Polymer Charge Transport Material for Ink-Jet OLEDs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional organic electroluminescent devices rely on small molecule materials for the hole transport layer, which are costly and difficult to process via wet methods due to poor solvent resistance, resulting in poor drive stability and efficiency compared to vacuum-evaporated devices.
Innovation Solution
A polymer with specific repeating units, including fluorene, benzene, and triarylamine moieties, is developed to serve as a charge transport material, enhancing luminescent efficiency and allowing for high-resolution ink-jet printing and improved solubility, suitable for use in light-emitting devices via wet processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small molecule materials are used for the hole transport layer and vacuum evaporation is employed, then the device can be fabricated, but the material cost is high and only 5% of materials are coated on the substrate
Solution Approach 1:
The patent changes the physical and chemical parameters of the charge transport material by using polymer materials with specific molecular structures (Formulas I and II) instead of small molecule materials. This parameter change enables the material to be processed via wet methods with high coating efficiency while reducing material waste, directly resolving the contradiction between productivity and substance loss.
2Ease of manufacture
If small molecule materials are used for the hole transport layer, then the layer can be fabricated by vacuum evaporation, but the solvent resistance is poor and wet process layering is difficult
Solution Approach 1:
The patent changes the material parameters from small molecules to polymers with specific structures (Formulas I and II), which fundamentally alters the solvent resistance properties. This enables the charge transport layer to be successfully fabricated via wet processes while maintaining compositional stability, resolving the contradiction between ease of manufacture and composition stability.
3Ease of manufacture
If wet process is used to fabricate devices, then the fabrication cost is reduced, but the drive stability and efficiency are poor compared to vacuum evaporation devices
Solution Approach 1:
The patent changes the material parameters to use polymers with specific structures (Formulas I and II) that are compatible with wet processes. This parameter change enables low-cost wet fabrication while achieving drive stability and efficiency comparable to vacuum evaporation devices, resolving the contradiction between ease of manufacture and reliability.
Data Source
AI summary
A polymer and a light-emitting device employing the same are provided. The polymer includes a first repeat unit with a structure represented by Formula (I):wherein the definitions of R1, R2, A1, A2, A3, and Z1 and n are as defined in the specification. At least one of A1, A2, and A3 is not hydrogen.