Self-Assembling Devices

Organic devices have greatly benefited from the remarkable advances in synthetic organic chemistry that have allowed for the synthesis of a wide variety of ð-conjugated molecules with attractive electronic functions.

In Chemistry—An Asian Journal, Wei-Shi Li, Takanori Fukushima, Takuzo Aida, and co-workers, based at the Shanghai Institute of Organic Chemistry (China), Riken (Saitama, Japan), and the Japan Science and Technology Agency (Tokyo) describe the rational design strategy using side-chain incompatibility of a covalently connected donor–acceptor (D–A) dyad to synthesize organic p/n heterojunctions with molecular-level precision.

Although organic devices can be easily designed, without proper molecular design that allows for long-range ordering of ð-conjugated molecules, the resulting devices will rarely show the expected performances. Thin-film organic photovoltaic devices require electron-donor (D) and -acceptor (A) molecules to assemble homotropically to form a heterojunction. Additionally, to achieve a highly efficient photoinduced charge separation, the resultant p- and n-type semiconducting domains must be connected over a long distance. However, D and A components tend to assemble together by means of a charge-transfer (CT) interaction, unfavorable for photoelectric conversion.

Oligothiophene (OT) and perylenediimide (PDI) have been synthesized to form covalently linked D–A dyads, which bear at their termini either incompatible or compatible side chains. The dyads with the incompatible side chains intrinsically self-assemble into nanofibrous structures, whilst the dyad containing the compatible side chains resulted in ill-defined microfibers. Flash-photolysis time-resolved microwave conductivity measurements, in conjunction with transient absorption spectroscopy, clearly shows that the assembly with the incompatible side chains exhibits a much greater photoconducting output than that with compatible side chains.

This design strategy with “side-chain incompatibility” provides promise for the realization of p/n heterojunctions from covalently connected D–A dyads. Furthermore, this design strategy can give rise to long-range structural integrity that is essential for excellent device performances. Aida writes “elaboration of side-chain-incompatible D–A dyads in terms of absorption range and carrier transport properties is a subject worthy of further investigations for developing molecularly engineered photovoltaic devices.”

Author: Takuzo Aida, National Museum of Emerging Science and Innovation, Tokyo (Japan), http://macro.chem.t.u-tokyo.ac.jp/

Title: Use of Side-Chain Incompatibility for Tailoring Long-Range p/n Heterojunctions: Photoconductive Nanofibers Formed by Self-Assembly of an Amphiphilic Donor-Acceptor Dyad Consisting of Oligothiophene and Perylenediimide

Chemistry – An Asian Journal, Permalink to the article: http://dx.doi.org/10.1002/asia.201000111

Media Contact

Takuzo Aida Wiley-VCH

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

The Sound of the Perfect Coating

Fraunhofer IWS Transfers Laser-based Sound Analysis of Surfaces into Industrial Practice with “LAwave”. Sound waves can reveal surface properties. Parameters such as surface or coating quality of components can be…

Customized silicon chips

…from Saxony for material characterization of printed electronics. How efficient are new materials? Does changing the properties lead to better conductivity? The Fraunhofer Institute for Photonic Microsystems IPMS develops and…

Acetylation: a Time-Keeper of glucocorticoid Sensitivity

Understanding the regulatory mechanism paves the way to enhance the effectiveness of anti-inflammatory therapies and to develop strategies to counteract the negative effects of stress- and age-related cortisol excess. The…

Partners & Sponsors