#oligomers

Twisted molecular wires exhibit high single-molecule conductance

From the high-voltage wires that carry electricity over long distances, to the tungsten filaments in our incandescent lights, we may have become accustomed to thinking that electrical conductors are always made of metal. But for decades, scientists have been working on advanced materials based on carbon-based oligomer chains that can also conduct electricity. These include the organic light-emitting devices found in some modern smartphones and computers. In quantum mechanics, electrons are not just point particles with definite positions, but rather can become 'delocalized' over a region. A molecule with a long stretch of alternating single- and double-bonds is said to have pi-conjugation, and conductive polymers operate by allowing delocalized electrons to hop between pi-conjugated regions—somewhat like a frog hopping between nearby puddles.

Ductile oligomeric acceptor enables highly efficient and mechanically robust flexible organic solar cells

A research group led by Prof. Ge Ziyi at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences has incorporated a ductile oligomeric acceptor (DOA) into the polymer donors and small molecule acceptors (PD:SMA) system, achieving flexible organic solar cells (OSCs) with high power conversion efficiency (PCE) and mechanical robustness. The study was published in Advanced Materials. Due to the advantages of light weight, flexibility, and processability, OSCs have been recognized as ideal candidates for flexible power sources. With the growth of the emerging market of wearable electronic devices, high PCE and mechanical robustness have shown their importance in the development of wearable applications of OSCs. However, compared with rigid OSCs, flexible OSCs exhibit relatively low PCEs (≈17%) and poor mechanical robustness. To address this issue, the researchers proposed a novel strategy that incorporates a DOA as a third component into the PD:SMA blend system of OSCs. Three DOAs, i.e., DOY-C2, DOY-C4, and TOY-C4, were synthesized with different flexible bridging chain segments and molecular chain lengths.

Perspective on oligomeric products from lignin depolymerization: Generation, identification and valorization

Lignin depolymerization is playing a pivotal role in transforming the second most abundant type of biopolymer in nature into many valuable chemicals/fuels. This route could directly replace their petrol-based equivalents and therefore presents a great pathway to fight climate change and contribute to future sustainability.

Interpretation of the reaction pathways helps with gaining an insightful mechanic view in understanding the depolymerization chemistry and paving new paths for lignin valorization at the industrial scale. However, such interpretation heavily relies on the state-of-art analytical capability, since in the process there are many oligomeric products formed but not well-characterized due to the limited instrumental analysis choices.

A team of scientists, therefore, summarized the considerable progress in the formation and identification of lignin oligomeric products in recent years. Both the existing and expected potential valorization routes are discussed, and technical hurdles and recommendations are provided in an attempt to catalyze the development of new discoveries and enabling technologies. The work is published in Industrial Chemistry & Materials.

Storing energy in plants with electronic roots

By watering bean plants (Phaseolus vulgaris) with a solution that contains conjugated oligomers, researchers at the Laboratory of Organic Electronics, Linköping University, have shown that the roots of the plant become electrically conducting and can store energy.

Dr. Eleni Stavrinidou, associate professor and principal investigator in the Electronic Plants Group at the Laboratory of Organic Electronics, showed in 2015 that circuits can be fabricated in the vascular tissue of roses. The conducting polymer PEDOT was absorbed by the plant´s vascular system to form electrical conductors that were used to make transistors. In a later work in 2017, she demonstrated that a conjugated oligomer, ETE-S, could polymerise in the plant and form conductors that can be used to store energy.

"We have previously worked with plant cuttings, which were able to take up and organize conducting polymers or oligomers. However, the plant cuttings can survive for only a few days, and the plant is not growing anymore. In this new study we use intact plants, a common bean plant grown from seed, and we show that the plants become electrically conducting when they are watered with a solution that contains oligomers," says Eleni Stavrinidou.

Jane Austen quote encoded in a polymer

Using a novel molecular-data-storage technique, researchers at the University of Texas at Austin have encoded a quote from Jane Austen's classic novel Mansfield Park in a series of oligomers, which a third party could read back without prior knowledge of the structures that encoded the passage. The findings, published April 21st in the journal Cell Reports Physical Science, illustrate a method to encode data that allows for greater information density than DNA-based approaches and that relies on urethane-like plastics—highly accessible and structurally modifiable chemical feedstocks—instead of nucleic acids.   

"This work is another step toward the long-term goal of using synthetic sequence-defined polymers for information storage," says Eric Anslyn, a chemistry professor at the University of Texas at Austin and an author of the study. "It sets the stage and hopefully inspires further work towards the practical use of molecules to usefully store information."

As society churns out enormous quantities of data, scientists are continuously seeking dense, durable, and cost-effective ways to store information. Molecular approaches offer a particularly appealing solution because they can retain information at far higher densities than leading silicon-based technologies.

Battling COVID-19: Researchers Discover Materials – Activated With UV Light – That Can Kill Coronavirus and Other Viruses

As the deadly COVID-19 pandemic continues to wreak havoc around the world with no end in sight, new ways in which to stop the spread or mitigate the effects of the disease are few.

Although most experts agree that a vaccine would significantly slow or eventually stop the spread, the work to develop, approve and distribute such a vaccine are likely months away. That leaves us with only prevention efforts such as masks, social distancing and disinfecting, which partially due to human inconsistencies in behavior, have proven to be variable in effectiveness.

Despite these grim realities about the novel coronavirus that has taken 2020 by storm, disrupting the work, school and personal lives of nearly everyone on the globe, some University of New Mexico researchers have found a possible breakthrough in how to manage this virus, as well as future ones.

Efficient fluorescent materials and OLEDs for the NIR

Near-infrared emitters (NIR) will be of crucial importance for a variety of biomedical, security and defense applications, as well as for (in)visible light communications and the internet-of-things (IoT). Researchers from the UK and Italy have developed porphyrin oligomer NIR emitters which afford high efficiencies despite being totally free from heavy metals. They demonstrated organic light-emitting diodes (OLEDs) at 850 nm with 3.8% peak external quantum efficiency, together with a novel quantitative model of device efficiency.

The ability to manipulate near-infrared (NIR) radiation has the potential to enable a plethora of technologies not only for the biomedical sector (where the semitransparency of human tissue is a clear advantage) but also for security (e.g. biometrics) and ICT (information and communication technology), with the most obvious application being to (nearly or in)visible light communications (VLCs) and related ramifications, including the imminent Internet of Things (IoT) revolution. Compared with inorganic semiconductors, organic NIR sources offer cheap fabrication over large areas, mechanical flexibility, conformability, and, potentially, bio-compatibility.

Lustrous metallic paints are used to enhance the beauty of many products, such as home decorations, cars and artwork. But most of these pigments owe their sheen to flakes of aluminum, copper, zinc or other metals, which have drawbacks. Now, researchers reporting in ACS Omega have developed organic-only dyes that can form films resembling gold or bronze, without the need for metals.

In paints, metal flakes tend to settle to the bottom of the can, requiring regular stirring during use and storage. Multiple coats of metallic paint are often needed to provide good coverage, which adds weight to the object being painted. Also, when used in ink-jet printers, metallic pigments can clog ink nozzles. For these and other reasons, researchers are trying to develop nonmetallic, organic paints with metal-like luster. But so far, few candidates have displayed all of the desired qualities of solubility in solvents, good film-forming properties and excellent stability over time. Katsuyoshi Hoshino and colleagues from Chiba University in Japan recently introduced a perchlorate-doped 3-methoxythiophene oligomer that checked all of these boxes, but it had to be dissolved in solvents that are considered unsafe for painters. To develop an industrially acceptable metal-effect dye, the researchers wanted to make and test chloride-doped 3-methoxythiophene oligomers.