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Exploring the origin of high optical absorption in conjugated polymers
Michelle S Vezie1, Sheridan Few1, Iain Meager2
1Centre for Plastic Electronics and Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK.
Nature Materials
|May 17, 2016
Summary
Organic semiconductors with high optical absorption are key for efficient optoelectronics. A specific copolymer
Area of Science:
- Materials Science, Organic Electronics, Photonics
Background:
- Organic semiconductors are crucial for optoelectronic devices, with optical absorption directly impacting performance.
- Efficient light harvesting is essential for applications like organic solar cells, especially when electrical transport is a limiting factor.
Purpose of the Study:
- To identify conjugated polymers with high optical absorption.
- To understand the structural factors contributing to enhanced optical absorption in organic semiconductors.
Main Methods:
- Comparative analysis of optical absorption spectra for over 40 conjugated polymers.
- Investigation of polymer backbone structure and conformation using experimental measurements.
- Utilizing quantum chemical calculations to correlate structure with optical properties.
Main Results:
- Many conjugated polymers exhibit a similar maximum extinction coefficient.
- A diketopyrrolopyrrole-thienothiophene copolymer demonstrated exceptionally high optical absorption at lower photon energies.
- High optical absorption in this copolymer is attributed to its high polymer persistence length.
Conclusions:
- Polymer persistence length is a critical factor for achieving high optical absorption in organic semiconductors.
- Judicious structural design, focusing on high persistence length, can significantly enhance visible light harvesting in conjugated polymers.
- This research provides insights for designing next-generation organic optoelectronic materials with improved light absorption capabilities.
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