Stable dinitrile end-capped closed-shell non-quinodimethane as donor, acceptor and additive of organic solar cells

Non-fullerene acceptors exhibit great potential to improve photovoltaic performances of organic solar cells. However, it is important to further enhance chemical stability and device durability for future commercialization, especially for Y6-series small molecule acceptors with 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) type as ending group. In this work, an IC-free photovoltaic material YF-CN consisting of 2-fluoren-9-ylidenepropanedinitrile terminal was designed and synthesized by stille coupling. YF-CN exhibited closed-shell chemical structure with enhanced photostability and improved morphological compatibility with the binary PCE10:Y6 blend. The moderate energy level makes YF-CN could serve as a multifunctional material, such as donor, acceptor and the third component. When adding YF-CN as second donor into PCE10:Y6 system, an improved power conversion efficiency of 12.03% was achieved for as-cast device. Importantly, the ternary PCE10:YF-CN:Y6-devices showed enhanced storage durability maintaining 91% of initial PCE after the 360 hours. This work provides new perspective to understand the open-shell character of donor and closed-shell structure of acceptors, respectively, as well as promising design concept of stable IC-free acceptors for organic solar cells.

Use of substitute Nonidet P-40 nonionic detergents in intracellular tubulin polymerization assays for screening of microtubule targeting agents

Shell Chemical Company Nonidet P-40 has been used for decades in many biochemical assays as a nonionic, nondenaturing detergent; however, Shell no longer manufactures this product. Four commercially available substitutes were investigated and their activities titrated in an intracellular tubulin polymerization assay. Although claimed by the supply companies to be identical to the Shell Nonidet P-40, all four substitutes were about 10-fold more potent and needed to be diluted accordingly. As microtubule targeting drugs are a major class of anticancer agent, and many researchers use the intracellular tubulin polymerization assay, this information is important to help troubleshoot assay development with the new substitutes. As the Shell Nonidet P-40 has been used in many biochemical buffers, these results will be of general interest to the biochemical, cell, and molecular research community.

Encores: Five More Bad Actors Were Dispatched

After DDT, EDF’s next pesticide targets were aldrin and dieldrin, both made by Shell Chemical Company. We had sought to block a dieldrin application in Michigan in late 1967, shortly after EDF was founded. That action was partly successful, delaying the application for many months and resulting in the application of less dieldrin. EDF was often accused of being against all pesticides, but that was never true. We were against DDT and several other persistent chlorinated hydrocarbons. Those pesticides were uniquely hazardous because they lasted for many years, traveled freely in the environment, and were ingested by animals and humans everywhere. They were very damaging to wildlife and—as we discovered along the way—they posed cancer hazards to humans. We were also against a purely chemical approach to pest control because integrated control techniques were more effective in controlling pests and contaminated the environment with less chemicals. We had a short list of pesticides that we identified as “bad actors”—all of which were persistent chlorinated hydrocarbons—and we eventually succeeded in getting all of them banned, although this took several years and an immense effort by our attorneys and scientists. On October 16, 1970, EDF filed a legal petition with HEW requesting the establishment of zero-tolerance levels for aldrin and dieldrin in human foods. The petition was written by attorney Edward Berlin and included a comprehensive review affidavit by me with numerous scientific references (Wurster, 1971). A few weeks later, pesticide regulation was transferred from HEW to the new EPA, and from then onward the action was pursued through EPA. I was not present during the hearing that followed. Instead Dr. Ian C. T. Nisbet, then the director of science for the Massachusetts Audubon Society, provided scientific support and attended the hearing. He wrote the next two sections (on aldrin and dieldrin and on heptachlor and chlordane), in which he describes what followed. On March 18, 1971, EPA issued notices of cancellation for all registrations of aldrin and dieldrin (A/D), but the marathon hearings did not begin until July 1973.

INFLUENCE OF INITIAL TEMPERATURES ON THE COOLING OF Ag–Pd BIMETALLIC CLUSTERS VIA MOLECULAR DYNAMICS SIMULATION

Atomic segregation in bimetallic clusters can influence the surface nucleation and also the structures of clusters. It is important to study the effect of atomic segregation on the structure. In this study, initial cooling temperatures were used to tune the atomic segregation ability. Molecular dynamics simulation with an embedded atom method was used to study the relationship between the structure and atomic segregation. It was found that the higher the initial cooling temperature, the more obvious the Ag atomic segregation. When the clusters cooled down from 800 K and 600 K, the clusters formed a mixed icosahedron due to the weak atomic segregation ability. When the initial cooling temperature is higher than 1200 K, all the Ag atoms segregated to the surface layer, the clusters formed a Pd – Ag -core–shell chemical ordering. For 1200 K initial temperature, the structure is decahedral. The clusters formed an fcc structure when the clusters cooled down from 2000 K, 1800 K, and 1500 K. When the clusters cooled down from 860 K and 900 K, not all the Ag atoms segregated to the surface layer, the clusters formed a core–shell chemical ordering with a mixed Pd – Ag core. But the structure of 860 K is twinned of icosahedron and decahedron and that of 900 K is decahedral. This means that the chemical orderings and structures were influenced by the atomic segregation.

A Novel Biocidal Elastomer

Biocidal elastomeric materials have been produced by a three-step chemical process on commercial elastomers which are composed of a styrene/ethylene-butylene/styrene triblock copolymer. The commercial elastomeric material employed was Kraton®G, produced by the Shell Chemical Company in Houston, Texas. The three-step process involved a Friedel-Crafts acylation of the styrene blocks of the elastomer, followed by a hydantoin ring formation reaction, and subsequent halogenation with chlorine or bromine. Both raw and processed elastomeric materials were studied. The biocidal efficacies of the materials were demonstrated using several species of bacteria. A few applications for the technology may include prevention of disease by biocidal surgical gloves, condoms, protective clothing, food packaging, and the prevention of biofouling in elastomeric tubing.