Conjugated Polymers for Organic Photovoltaics
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Solution Overview
Problem
Conjugated polymers used in organic photovoltaic devices face limitations such as limited solubility in organic solvents, low charge carrier mobility, and stability issues, which hinder their suitability for large-scale production and efficient light harvesting.
Innovation Solution
Development of conjugated polymers containing thieno[3,2-b]thiophene-2,5-dione and furo[3,2-b]furan-2,5-dione repeating units and their thioketone derivatives, which exhibit high solubility, charge carrier mobility, and oxidative stability, enabling their use as semiconductors in organic electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional conjugated polymers are used in OPV devices, then device manufacturing by solution processing is enabled, but the polymers suffer from limited solubility in organic solvents which inhibits suitability for large-scale production
Solution Approach 1:
The patent modifies the chemical structure of conjugated polymers by incorporating specific electron-deficient units (thieno[3,2-b]thiophene-2,5-dione, furo[3,2-b]furan-2,5-dione) and electron-rich units with varying side chains. This changes the chemical parameters of the polymer to achieve both high solubility in common organic solvents and low band gap for efficient light harvesting, resolving the contradiction between solution processing capability and solubility.
2Use of energy by moving object
If conjugated polymers are designed with narrow band gap to absorb maximum solar spectrum, then light harvesting efficiency is improved, but charge carrier mobility remains limited
Solution Approach 1:
The patent creates composite polymer structures by alternating electron-deficient units (thieno[3,2-b]thiophene-2,5-dione or furo[3,2-b]furan-2,5-dione) with electron-rich units. This composite approach allows the electron-deficient units to provide narrow band gap for efficient light harvesting while the electron-rich units with appropriate side chains maintain good charge carrier mobility and solubility, thus resolving the contradiction between light harvesting efficiency and charge carrier mobility.
3Quantity of substance
If conjugated polymers are synthesized by conventional methods, then polymer production is achieved, but the synthesis methods are unsuitable for mass production
Solution Approach 1:
The patent designs polymers with modular repeating units that can be synthesized through step-growth polymerization using commercially available monomers. The segmentation of the polymer into standardized electron-deficient and electron-rich units enables scalable synthesis methods suitable for mass production, while maintaining the desired optical and electrical properties.
4Productivity
If conjugated polymers are used to achieve high efficiency OPV devices, then device performance is improved, but the polymers exhibit poor stability in air
Solution Approach 1:
The patent employs thieno[3,2-b]thiophene-2,5-dione and furo[3,2-b]furan-2,5-dione units which inherently possess high oxidative stability due to their electron-deficient nature and aromatic structure. These units act as stable backbones that resist degradation in air, enabling high-efficiency OPV devices with improved long-term stability without requiring complex protective measures.
Data Source
Figure 1
AI summary
The invention relates to novel polymers containing one or more thieno[3,2- b]thiophene-2,5-dione and/or furo[3,2-b]furan-2,5-dionerepeating units or their thioketone derivatives, monomers and methods for their preparation, their use as semiconductors in organic electronic (OE) devices, especially in organic photovoltaic (OPV) devices, and to OE and OPV devices comprising these polymers.