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Updated: Mar 7, 2026
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
9.0K
Visualizing excitations at buried heterojunctions in organic semiconductor blends.
Andreas C Jakowetz1, Marcus L Böhm1, Aditya Sadhanala1
1Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
Nature Materials
|February 21, 2017
Summary
A new all-optical method reveals that ordered sites at polymer/fullerene interfaces are crucial for efficient charge separation in organic electronics. Ultrafast hole migration to these sites aids in overcoming charge recombination barriers.
Area of Science:
- Semiconductor physics
- Materials science
- Organic electronics
Background:
- Interfaces are critical in semiconductor devices but challenging to study.
- Nanostructured and buried interfaces lack specific information from conventional probes.
Purpose of the Study:
- Develop an all-optical, time-resolved method to probe interfaces.
- Investigate the energetic landscape and electronic dynamics at polymer/fullerene interfaces.
Main Methods:
- Utilized the Stark effect from photo-generated electron-hole pairs across the interface.
- Employed an all-optical, time-resolved technique for interface analysis.
Main Results:
- Identified electronically active sites at polymer/fullerene interfaces within the low-energy absorption spectrum tail.
- Observed a 100 fs hole migration from higher- to lower-energy sites, indicating ballistic motion into ordered polymer regions.
- Found evidence of high ordering and large wavefunction delocalization at active interface sites.
Conclusions:
- The developed method provides crucial interface-specific information.
- Highly ordered sites at polymer/fullerene interfaces facilitate efficient charge separation.
- Ultrafast charge motion is key to overcoming Coulombic interactions for charge separation.
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