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Morphology Control for Fully Printable Organic–Inorganic Bulk-heterojunction Solar Cells Based on a Ti-alkoxide and Semiconducting Polymer
Published on: January 10, 2017
Electronic structure and interface properties of a model molecule for organic solar cells
Holger Hintz1, Heiko Peisert, Umut Aygül
1Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany.
We investigated the electronic structure of 4,7-bis(5-methylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (MTBT), a model for solar cell materials. A strong interaction between MTBT
Area of Science:
- Materials Science
- Organic Electronics
- Physical Chemistry
Background:
- 4,7-bis(5-methylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (MTBT) serves as a model compound for poly[2,5-bis(3,4-ethylenedioxythiophen-2-yl)thieno[3,2-b]thiophene] (PCPDTBT).
- PCPDTBT is a key material in the development of efficient bulk heterojunction solar cells.
Purpose of the Study:
- To elucidate the electronic structure of MTBT.
- To investigate the interface properties of MTBT with gold.
- To understand the fundamental interactions influencing organic electronic device performance.
Main Methods:
- X-ray Photoemission Spectroscopy (XPS)
- Valence-band Ultraviolet Photoemission Spectroscopy (UPS)
- X-ray Absorption Spectroscopy (XAS)
- Resonant Photoemission Spectroscopy (ResPES)
Main Results:
- The highest occupied molecular orbital (HOMO) of MTBT shows minimal contribution from sulfur and a weak contribution from nitrogen.
- A significant chemical interaction is observed between the sulfur atoms of the benzothiadiazole unit and the gold interface.
- Spectroscopic analysis reveals detailed electronic and interfacial characteristics of the MTBT molecule.
Conclusions:
- The electronic structure of MTBT is characterized, with specific insights into the HOMO level composition.
- The strong sulfur-gold interaction at the interface suggests potential implications for charge transfer and device stability in organic solar cells.
- This study provides crucial data for the design and optimization of organic semiconductor interfaces for photovoltaic applications.
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