We reviewed the current state of the art of poly(ethylene terephthalate) (PET) chemolysis used in the chemical recycling of PET.

Restoring the environmental balance that was disturbed by the rise of plastic commodities is a must for researchers and the wider community. It is imperative that the increasing amount of...

A number of groups have invested considerable time synthesizing double-decker silsesquioxane (DD SQ) copolymers; however, to our knowledge, no one has sought to explore through-chain electronic communication between DD SQs via “conjugated” co-monomers. We recently demonstrated that stilbene derivatives of simple DD cages exhibit properties commensurate with formation of cage centered lowest unoccupied molecular orbitals (LUMOs), equivalent to LUMOs found in complete/incomplete SQ cages, [RStilbeneSiO1.5]8,10,12, [RStilbeneSiO1.5]7[O1.5SiMe/nPr], [RStilbeneSiO1.5]7[O0.5SiMe3]3, [RStilbeneSiO1.5]8[O0.5‑SiMe3]4, and [RStilbeneSiO1.5]8[OSiMe2]2. Such LUMOs support the existence of 3D excited-state conjugation in these cages. We describe here Heck catalyzed copolymerization of vinyl­(Me)­SiO­(PhSiO1.5)8OSi­(Me)­vinyl (vinylDDvinyl) with X–Ar–X, where X = Br or I and X–Ar–X = 1,4-dihalobenzene, 4,4′-dibromo-1,1′-biphenyl, 4,4″-dibromo-p-terphenyl, 4,4′-dibromo-trans-stilbene, 2,5-dibromothiophene, 5,5′-dibromo-2,2′-bithiophene, 2,5-dibromothieno­[3,2-b]­thiophene, and 2,7-dibromo-9,9-dimethylfluorene. Coincidentally model analogs were synthesized from vinylMeSi­(OMe)2. All compounds were characterized in detail by gel permeation chromatography (GPC), matrix-assisted laser desorption/ionization-time-of-flight, thermogravimetric analysis, nuclear magnetic resonance, Fourier transfer infrared spectroscopy, ultraviolet–visible spectroscopy, photoluminescence spectrometry, and two-photon absorption (2PA) spectroscopy. Modeling of HOMO–LUMO energy levels of related compounds with R = Me rather than Ph was also explored. In the current systems, we again see apparent conjugation in excited states, as previously observed, as indicated by 50–120 nm red shifts in emission from the corresponding model silane compounds. These results suggest unexpected semiconducting behavior via vinylMeSi­(O−)2 (siloxane) bridges between DD cages in polymers. The thiophene, bithiophene, and thienothiophene copolymers display integer charge transfer behavior on doping with 10 mol % F4TCNQ supporting excited-state conjugation; suggesting potential as p-type, doped organic/inorganic semiconductors.

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Conjugated polymers are a special type of material responsible for light absorption in polymer solar cells. The absorption of these materials plays an important role in photon harvesting and energy conversion. Ternary organic solar cells are a type of OPV that combines two‐electron donors with complementary absorption in a single layer. The present work deals with the synthesis and characterization of a high‐bandgap polymer prepared through the alternation of two high‐electron density aromatic units (thiophene‐benzodithiophene). This polymer presented high bandgap (2.1 eV) with potential for complementary absorption in a ternary device, as well as high Voc when applied in a single junction inverted OPV device in heterojunction with PC70BM (0.95 V), which agrees with the relatively large energy difference between its HOMO and the LUMO of PC70BM determined through CV and UV‐vis. A dynamic GIWAXS study was performed and demonstrated that for this polymer, increasing annealing temperature to 80°C can increase its crystalline organization by up to 50%.

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