Diketopyrrolopyrrole Polymers for PLED Solubility and Mobility
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Solution Overview
Problem
Current polymeric electroluminescent materials based on diketopyrrolopyrrole (DPP) moieties lack specific guidance for use in illumination or display devices, particularly in terms of improving device properties such as solubility, film-forming properties, charge carrier mobilities, and temperature stability in polymer light-emitting diodes (PLEDs).
Innovation Solution
Development of conjugated polymers with a specific repeating unit formula, incorporating DPP moieties, which exhibit excellent solubility in organic solvents, high charge carrier mobilities, and high temperature stability, along with the inclusion of additional repeating units to enhance hole-injection, electron-injection, and electron-transport properties, thereby optimizing performance in PLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DPP-based polymers are used in PLEDs, then charge carrier mobilities and temperature stability are improved, but solubility and film-forming properties are insufficient
Solution Approach 1:
The patent introduces specific side chain structures (alkoxy-substituted aryl groups) at localized positions on the DPP core to improve solubility without compromising the core's charge transport properties. The side chains are strategically positioned to provide steric bulk and solubility enhancement while maintaining the planar conjugated system's electronic properties.
Solution Approach 2:
The patent creates composite polymer structures by combining DPP core units with diverse side chain components (aromatic rings, alkoxy groups, alkyl chains). This composite approach allows the material to simultaneously exhibit the high charge carrier mobility of the conjugated DPP backbone and the improved solubility/film-forming properties of the side chain components.
2Device complexity
If conventional DPP polymers are used, then device structure is simple, but device performance (current density, electroluminescence) is insufficient
Solution Approach 1:
The patent systematically varies key structural parameters of the DPP polymer including side chain length, aromatic substitution patterns, and polymerization degree to optimize device performance. By adjusting these parameters, the material achieves enhanced current density and electroluminescence intensity while maintaining reasonable structural complexity.
3Reliability
If DPP polymers with extended conjugation are synthesized, then charge carrier mobilities increase, but solubility decreases
Solution Approach 1:
The patent introduces solubility-enhancing side chains (alkoxy-substituted aryl groups) at specific localized positions on the DPP core, allowing the extended conjugated system to maintain high charge carrier mobility while the localized side chains provide the necessary solubility through steric bulk and enhanced intermolecular interactions with solvents.
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 polymers demonstrate improved current density and electroluminescence at lower voltages, making them suitable for mobile applications like displays in phones and PDAs, with the ability to vary electronic band gaps for color property adjustment.
Implementation Method 1
high charge carrier mobilities and high temperature stability of the emission color can be observed, if the polymers according to the invention are used in polymer light emitting diodes (PLEDs)
Data Source
AI summary
The present invention relates to polymers comprising a repeating unit of the formula (I) their use in electronic devices. The polymers according to the invention have excellent solubility in organic solvents and excellent film-forming properties. In addition, high charge carrier mobilities and high temperature stability of the emission color are observed, if the polymers according to the invention are used in polymer light emitting diodes (PLEDs).