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A benzothiadiazole end capped donor-acceptor based small molecule for organic electronics
Prashant Sonar1, Evan L Williams, Samarendra P Singh
1Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research (A*STAR), 3 Research Link, Singapore 117602. sonarp@imre.a-star.edu.sg.
Physical Chemistry Chemical Physics : PCCP
|September 14, 2013
Summary
A novel benzothiadiazole end-capped small molecule was synthesized for organic electronics. This material shows promise in organic field-effect transistors and organic photovoltaics, demonstrating good charge mobility and power conversion efficiency.
Area of Science:
- Organic electronics
- Materials science
- Condensed matter physics
Background:
- Small molecules are crucial for organic electronic devices.
- Donor-acceptor (D–A) structures are widely investigated for their optoelectronic properties.
- Benzothiadiazole and diketopyrrolopyrrole (DPP) moieties are common building blocks in high-performance organic semiconductors.
Purpose of the Study:
- To design and synthesize a novel benzothiadiazole end-capped small molecule with a D–A–D structure.
- To investigate the optoelectronic properties and solid-state ordering of the synthesized molecule.
- To evaluate the performance of the molecule in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs).
Main Methods:
- Chemical synthesis of the benzothiadiazole end-capped small molecule (BO-DPP-BTZ).
- Optical absorption spectroscopy to study solution and thin-film properties.
- Fabrication and characterization of OFETs using spin-coated thin films.
- Fabrication and characterization of bulk heterojunction OPVs using a blend with [70]PCBM.
Main Results:
- The synthesized molecule, BO-DPP-BTZ, has a D–A–D structure with a band gap of 1.6 eV.
- Strong solid-state ordering was observed, indicated by a significant red shift in absorption from solution to thin film.
- OFETs fabricated with BO-DPP-BTZ exhibited a hole mobility of 0.06 cm² V⁻¹ s⁻¹.
- Solution-processed bulk heterojunction OPVs achieved a power conversion efficiency of 0.9%.
Conclusions:
- The designed benzothiadiazole end-capped small molecule demonstrates favorable optoelectronic properties for organic electronics.
- The material's solid-state ordering contributes to its performance in OFETs.
- BO-DPP-BTZ shows potential for use in solution-processed organic electronic devices, including OPVs.
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