Organic Semiconductor Polymer for Flexible Displays
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Solution Overview
Problem
Existing organic thin film transistors using organic semiconductors face limitations in charge mobility and solubility, making them unsuitable for large-area flexible displays and solution processing.
Innovation Solution
Development of an organic semiconductor polymer with a heteroaromatic moiety containing sulfur or selenium, which enhances charge mobility and solubility, allowing for improved thin film characteristics and bipolar characteristics, enabling higher charge mobility and lower leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional organic semiconductors are used in thin film transistors, then the device can be manufactured using solution processes, but the charge mobility is insufficient for high-performance applications
Solution Approach 1:
The patent employs composite material design by combining electron-donating groups (such as carbazole, triphenylamine) with electron-accepting groups (such as diketopyrrolopyrrole, naphthalimide) to create ambipolar semiconductor polymers. This composite structure enables the material to simultaneously achieve good solubility for solution processing and high charge mobility through enhanced intermolecular interactions and charge transport pathways
Solution Approach 2:
The patent applies parameter changes by systematically varying the molecular weight, polydispersity index, and chemical structure of the semiconductor polymers. By optimizing these parameters, the material achieves both solution processability (through appropriate molecular weight and solubility) and high charge mobility (through optimized packing and intermolecular interactions)
2Reliability
If organic semiconductor polymers are designed for high charge mobility, then charge transport improves, but solubility and processability deteriorate
Solution Approach 1:
The patent applies local quality by introducing specific functional groups at particular positions within the polymer chain. Electron-donating groups are placed at terminal positions to enhance solubility, while electron-accepting groups are positioned in the backbone to promote charge transport. This spatial differentiation of functional groups allows simultaneous optimization of solubility and charge mobility
Solution Approach 2:
The patent uses solubilizing side chains and flexible linker groups as intermediaries between the rigid charge-transporting backbone and the solvent environment. These intermediary groups maintain the structural integrity and charge transport pathways while providing sufficient solubility for solution processing
3Device complexity
If conventional organic semiconductors are used, then the structure is simpler, but the leakage current is high and bipolar characteristics are insufficient
Solution Approach 1:
The patent merges electron-donating and electron-accepting functionalities into a single ambipolar semiconductor polymer molecule. This combination enables the material to transport both electrons and holes effectively, achieving low leakage current and bipolar characteristics while maintaining relatively simple polymer structures that can be processed using conventional solution methods
Data Source
AI summary
An organic semiconductor polymer includes a moiety represented by the following Chemical Formula 1 and a heteroaromatic moiety having at least one of sulfur (S) and selenium (Se).In the Chemical Formula 1, R1, R2, R3a, R3b, R4a, R4b, R5a, and R5b, a1, a2, b1, and b2 are the same as described in the detailed description.