Polymer Linker Reduces Steric Hindrance in OLED Hole Transport
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Solution Overview
Problem
Current organic light emitting devices face challenges in achieving simultaneous solubility in solvents and hole transport characteristics, particularly in the solution process, due to steric hindrance issues with arylamine-based materials.
Innovation Solution
A novel polymer with a specific repeating unit structure, represented by Chemical Formula 1, is introduced, which includes an appropriate linker (L1) between the main chain and the arylamine-based core, reducing steric hindrance and enhancing solubility and hole transfer properties, allowing for the formation of a hole transport or injection layer that can be deposited by a solution process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If arylamine-based materials are used for hole transport, then hole transport characteristics are improved, but solubility in solvents deteriorates due to steric hindrance
Solution Approach 1:
The arylamine-based core is segmented from the main chain by introducing a linker (L1) group, which separates the bulky arylamine core from the polymer backbone. This segmentation reduces steric hindrance between the core and main chain, thereby improving solubility while preserving the hole transport characteristics of the arylamine core.
Solution Approach 2:
A linker (L1) group is introduced as an intermediary between the main chain and the arylamine-based core. This intermediary component acts as a buffer that reduces steric interactions, allowing the arylamine core to maintain its hole transport function while the linker improves overall solubility by reducing crowding effects.
2Ease of manufacture
If solution process is used for deposition, then process cost is reduced, but manufacturing precision deteriorates due to limitations in current technology
Solution Approach 1:
The polymer structure is modified by changing parameters such as introducing flexible linker groups and adjusting the molecular weight and composition. These parameter changes improve solubility and film-forming properties, enabling high-quality deposition through solution processes like inkjet printing, thereby achieving both cost reduction and maintained manufacturing precision.
3Ease of manufacture
If polymer structure is modified to improve solubility, then ease of manufacture is improved, but device complexity increases
Solution Approach 1:
Instead of modifying the entire polymer structure uniformly, the invention applies local quality changes by introducing linkers specifically at strategic positions between the main chain and arylamine cores. This localized modification improves solubility without requiring complex changes throughout the entire polymer architecture, thus limiting the increase in device complexity.
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 polymer improves the efficiency, reduces driving voltage, and enhances the lifetime characteristics of organic light emitting devices by facilitating a solution process for the hole transport or injection layer, resulting in superior performance compared to traditional materials.
Implementation Method 1
the holes are injected from an anode into the organic material layer and the electrons are injected from the cathode into the organic material layer, and when the injected holes and electrons meet each other, an exciton is formed
Implementation Method 2
an organic light emitting device using a solution process, particularly an inkjet process, has been developed instead of a conventional deposition process
Implementation Method 3
electric energy is converted into light energy by using an organic material
Data Source
AI summary
The present invention provides a novel polymer comprising repeating unit represented by the following Chemical Formula 1, and an organic light emitting device including the same:Wherein L1, L2, Ar1, Ar2, Ar3, R1 to R8, o, p and n are described herein.