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
Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine
New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Life Sciences
26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology