Bi-indoline-dithione Polymers for High-Mobility OTFTs
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Solution Overview
Problem
Organic thin-film transistors (OTFTs) face limitations due to low field-effect mobility, air sensitivity, and limited solubility of polymeric semiconductors, which hinder their performance and stability in electronic devices.
Innovation Solution
Development of semiconducting polymers containing a dithioisoindigo moiety, specifically with structures described by Formula (I), which exhibit high field-effect mobility, air stability, and good solubility, enabling their use in semiconducting layers of thin-film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic or polymeric semiconductors are formed by solution processing, then low-cost fabrication is enabled, but field-effect mobility remains low
Solution Approach 1:
The patent modifies the molecular structure of the semiconductor polymer by incorporating specific heterocyclic rings (thiophene, selenophene, carbazole) and adjusting conjugation length and side chain configurations. These structural parameter changes enable the material to maintain high field-effect mobility (exceeding 1 cm²/Vs) while remaining processable by solution methods, thus resolving the contradiction between low-cost fabrication and high mobility performance
Solution Approach 2:
The patent creates composite polymer structures combining electron-rich heterocyclic units with electron-deficient units to form donor-acceptor type copolymers. This composite approach at the molecular level optimizes both charge transport properties (mobility) and solution processability, allowing the material to achieve high performance through solution-based fabrication without sacrificing mobility
2Reliability
If small molecule semiconductors are used, then high mobility can be achieved, but film-forming properties are poor
Solution Approach 1:
The patent divides the semiconductor material into polymeric chains with repeating units containing heterocyclic structures. This segmentation into polymer segments maintains the high mobility characteristics of small molecules through preserved conjugation and molecular packing, while the polymeric nature provides superior film-forming properties and mechanical stability, resolving the contradiction between mobility and film quality
Solution Approach 2:
The patent adjusts polymer chain parameters including molecular weight, polydispersity, and side chain length to optimize film formation. By controlling these parameters, the material achieves both high field-effect mobility and excellent film-forming properties, enabling solution processing to produce high-quality semiconductor layers
3Ease of manufacture
If polymeric semiconductors are used, then solubility and processability improve, but air stability deteriorates
Solution Approach 1:
The patent introduces specific heterocyclic units (thiophene, selenophene, carbazole) with inherent oxidative stability at critical positions in the polymer backbone. These locally optimized units provide resistance to air oxidation while maintaining overall polymer solubility through appropriate side chain selection, thus resolving the contradiction between solubility and air stability
Solution Approach 2:
The patent designs donor-acceptor copolymers where electron-rich and electron-deficient units alternate in the backbone. This composite structure creates a balanced electronic distribution that reduces susceptibility to oxidative degradation from air, while the amphiphilic character of the composite structure maintains good solubility in common organic solvents
Data Source
AI summary
A polymer of Formula (I)wherein Ar, R1, R2, R3, R4, Y, x, k, m, and n are as described herein. The polymer may be used in a semiconducting layer of an electronic device.