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ABSTRACT The synthesis and characterization of two low band gap copolymers ( P1 and P2) incorporating benzo[1,2- b:4,5- b']dithiophene unit substituted with octylsulfanylthienyl groups (OSBT) are here reported. These materials, designed to be employed in polymer solar cells (PSCs), were obtained from alternating OSBT and bithiophene ( P1) or thienothiophene ( P2) units. Their structural electrochemical and photophysical properties were investigated. They are thermally stable and soluble in organic solvents from which they easily form films. They also form π-stacks in solution, in film and display a moderate solvatochromism. These polymers were tested with [70]PCBM in bulk-heterojunction (BHJ) PSCs where they act as donor materials and [70]PCBM is the electron acceptor. The best device, obtained using a 1:3 weight ratio for the P1:[70]PCBM blend, shows a PCE around 1.5%. A broad response from 350 to 700 nm is also observed in the external quantum efficiency (EQE) curves, wider for P1 with respect to P2. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1603-1614 [ABSTRACT FROM AUTHOR]

A detailed study of reduction potentials, electroreduction mechanisms, and acid-base chemistry was carried out on two series of free-base porphyrins in nonaqueous media. The first series is represented by four β-pyrrole-substituted tetraphenylporphyrin (TPP) derivatives, two of which are planar and two of which are nonplanar in their nonprotonated form. The second comprises porphyrins with 0-4 meso-phenyl groups on the macrocycle. Equilibrium constants for the conversion of each neutral porphyrin to its diprotic [H4P]2+ form were determined and the electrochemistry was then elucidated as a function of: 1) type of nonaqueous solvent, 2) anion of supporting electrolyte, 3) porphyrin ring substituents, and 4) concentration of acid added to solution. Spectroelectrochemistry was used to characterize absorption spectra of each electroreduced species and, when combined with results of the above studies, significantly improves our ability to tune redox reactivity of these types of compounds. [ABSTRACT FROM AUTHOR]

Many research efforts are focused toward significant improvements of polymeric solar cells efficiency, energy harvesting range, time, and environmental stability. Particular attention is given to hybrid organic/inorganic composites constituted of polymer/lead chalcogenides (PbS and PbSe) nanocrystals (NCs) to extend the spectral sensitivity of cells to near-infrared wavelengths. In this work we report the synthesis and characterization of PbS nanocrystals with absorption edge at 984 nm. The nanocrystals have a cubic crystal structure and size of about 2 nm as found by X-ray diffraction analysis. They were combined with poly(3-hexylthiophene) (P3HT) polymer to obtain P3HT:PbS blends with different PbS loadings. A post-deposition ligand exchange on PbS NCs by 1,2-ethanedithiol (EDT) allowed a better interaction between polymer and nanocrystals as showed by fluorescence measurements. The P3HT:PbS blends were deposited and treated by a layer by layer spin coating process and used as active layer in solar cells having structure glass/ITO/PEDOT:PSS/blend/Al. The major result obtained for this hybrid system is an increase of PCE by about two orders of magnitude with respect to analogous reported cells where a post-deposition ligand exchange was performed. [ABSTRACT FROM AUTHOR]

Monolithic aerogels can be easily obtained by drying physical gels formed by linear uncross-linked polymers. Preparation methods, structure, and properties of these physically cross-linked polymeric aerogels are reviewed, with particular emphasis to those whose cross-linking knots are crystallites and, more in particular, crystallites exhibiting nanoporous-crystalline forms. The latter aerogels present beside disordered amorphous micropores (typical of all aerogels) also all identical nanopores of the crystalline phases. Their outstanding guest transport properties combined with low material cost, robustness, durability, and ease of handling and recycle make these aerogels suitable for applications in chemical separations, purification, and storage as well as in biomedicine. Scientific, technological, and industrial perspectives for monolithic nanoporous-crystalline polymeric aerogels are also discussed. [ABSTRACT FROM AUTHOR]