Understanding the influence of polymer molecular weight on the morphology, photophysics, and photovoltaic properties of polymer solar cells is central to further advances in the design, processing, performance and optimization...

A general and effective CuI/N',N'-diaryl-1H-pyrrole-2-carbohydrazide catalyst system was developed for the amination of aryl iodides and bromides at room temperature with good chemoselectivity between -OH and -NH groups. Only 5 mol % of CuI and ligands was needed in this protocol to effect the amination of various aryl bromides and aryl iodides with a wide range of aliphatic and aryl amines (1.3 equiv).

Improving carrier mobility, redox stability, blend morphology, and photovoltaic performance while elucidating structure–property relationships remains an important design goal for nonfullerene electron acceptors (NFAs) for organic solar cells. Although numerous NFAs have been created from rylene diimide electron-deficient building blocks, they have shown far inferior photovoltaic properties compared to benchmark fused-ring electron acceptors (FREAs) such as ITIC. Herein we show that new bis­(naphthalene-imide)­arylenelidenes (BNIAs), incorporating rylene-imide end-capping groups via methine bridges in donor–acceptor architectures, are endowed with enhanced electrochemical redox stability, high carrier mobilities, and high photovoltaic performance. Pairing of those BNIAs that are also FREAs, NIDT and NIBT, respectively, with donor polymer PBDB-T produced 10.0–10.8% efficient photovoltaic devices, which are comparable to benchmark ITIC devices. Blends of FREAs NIDT and NIBT and those of non-FREA NITV were found to have similar electron mobilities, demonstrating that the much higher photovoltaic efficiency of NIDT and NIBT devices does not originate from enhanced charge transport but from differences in blend morphology and blend photophysics. The results demonstrate that incorporating rylene imides into molecular architectures through the methine-bridged donor–acceptor coupling motif is a promising design strategy toward more efficient and electrochemically rugged materials for organic solar cells.

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Effects of the donor moiety substitution on the intrinsic and photovoltaic blend properties of n-type semiconducting naphthalene diimide-arylene copolymers with donor−acceptor structure were investigated. The alternating naphthalene diimide-thiophene copolymer, PNDIT-hd, and naphthalene diimide-selenophene copolymer, PNDIS-hd, were found to have identical electrochemically derived electronic structures and similar bulk electron mobility; however, PNDIShd has an optical bandgap of 1.70 eV, which is 0.07 eV narrower relative to that of PNDIT-hd. All-polymer solar cells incorporating the donor polymer, PBDB-T, and PNDIS-hd were found to combine a high power conversion efficiency of 8.4% with high external quantum efficiency (86%) and a high fill factor of 0.71, which are significantly enhanced compared to the corresponding PBDB-T:PNDIT-hd devices with 6.7% power conversion efficiency and 73% external quantum efficiency. The improved photovoltaic properties of the selenophene-containing acceptor copolymer relative to the thiophene counterpart originate from enhanced light harvesting, more favorable molecular packing in blends, and reduced charge recombination losses in devices. These findings demonstrate that selenophene substitution for thiophene in donor− acceptor copolymers is an effective strategy that enhances the intrinsic polymer properties as well as the performance of all-polymer solar cells incorporating them.

Polyoxometalates (POMs) are widely used in the preparation of sensors that detect the content of substances because of their excellent electron transfer capabilities. In this paper, the [(PSS/PPy)(P2Mo18/PPy)5] multilayer composite...

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Fifteen 2-(5-(aryloxymethyl)-1,3,4-thiadiazol-2-ylthio)-N-arylacetamides were efficiently synthesized from the reaction of 2-chloro-N-arylacetamide with 5-(aryloxymethyl)-1,3,4-thiadiazole-2-thiol under solvent-free conditions at room temperature via grinding. The key advantages of the method are the short reaction time, high yields, simple workup, and environmentally friendly conditions compared to conventional heating.