A 1,8-Naphthalimide-based Tripodal Fluorescent Chemosensor to Selectively Detect Copper Ions.

A 1,8-naphthalimide-based tripodal fluorescent ligand (L3) was synthesized through the copper (I) catalyzed Huisgen azide-alkyne cycloaddition reaction of 2-(2-azidoethyl)-6-morpholino-1 H-benzo[de]isoquinoline-1,3(2 H)-dione with triproparagylamine. Naphthalimide acts as the fluorophore while the triazole and amine nitrogens chelate the metal ion. L3 showed a selective fluorescence turn-off for Cu(II) over other metal ions in aqueous acetonitrile solution.

Single-junction polymer solar cells with over 10% efficiency by a novel two-dimensional donor-acceptor conjugated copolymer.

Recent advances in bulk heterojunction (BHJ) polymer solar cell (PSC) performance have resulted from compressing the band gap to enhance the short-circuit current density (JSC) while lowering the highest occupied molecular orbital to increase the open-circuit voltage (VOC) and consequently enhance the power conversion efficiencies (PCEs). However, PCEs of PSCs are still constrained by a low JSC, small VOC, and low fill factor (FF). In this study, we report 10.

Molecular structure of poly(methyl methacrylate) surface. I. Combination of interface-sensitive infrared-visible sum frequency generation, molecular dynamics simulations, and ab initio calculations.

The chemical composition and molecular structure of polymeric surfaces are important in understanding wetting, adhesion, and friction. Here, we combine interface-sensitive sum frequency generation spectroscopy (SFG), all-atom molecular dynamics (MD) simulations, and ab initio calculations to understand the composition and the orientation of chemical groups on poly(methyl methacrylate) (PMMA) surface as a function of tacticity and temperature. The SFG spectral features for isotactic and syndiotactic PMMA surfaces are similar, and the dominant peak in the spectra corresponds to the ester-methyl groups.

Effect of fluorination on electronic properties of polythienothiophene-co-benzodithiophenes and their fullerene complexes.

Fluorination of conjugated polymers is a popular way of designing new electron donors for the bulk heterojunction (BHJ) based organic solar cells (OSCs). However, not all fluorinated polymers observed experimentally enhance the power conversion efficiency of OSCs, and the fundamental understanding of the effect of fluorination is not yet fully uncovered. Herein, we report the effect of fluorine substitution on the electronic properties of polythienothiophene-co-benzodithiophenes as well as their complexes with fullerene, using density functional theory (DFT) and time-dependent DFT methods at the molecular level.

Nanostructures and electronic properties of a high-efficiency electron-donating polymer.

The development of organic photovoltaic (OPV) solar cells has seeded a bright hope of achieving low-cost solar energy harvesting. Practical realization and successful commercialization require enhancing the efficiency of solar energy harvesting, which, in turn, relies on the core understanding of structure-property relationships in OPV materials. Here, we report the first large-scale density functional calculations of the nanoconformational and electronic properties of the thieno[3,4-b]thiophene-alt-benzodithiophene copolymer (PTB7), a high-efficiency OPV material.

Torsion-inversion tunneling patterns in the CH-stretch vibrationally excited states of the G12 family of molecules including methylamine.

Two torsion-inversion tunneling models (models I and II) are reported for the CH-stretch vibrationally excited states in the G12 family of molecules. The torsion and inversion tunneling parameters, h(2v) and h(3v), respectively, are combined with low-order coupling terms involving the CH-stretch vibrations. Model I is a group theoretical treatment starting from the symmetric rotor methyl CH-stretch vibrations; model II is an internal coordinate model including the local-local CH-stretch coupling.

Improved force field for molecular modeling of poly(3-hexylthiophene).

An ab initio-based improved force field is reported for poly(3-hexylthiophene) (P3HT) in the solid state, deriving torsional parameters and partial atomic charges from ab initio molecular structure calculations with explicit treatment of the hexyl side chains. The force field is validated by molecular dynamics (MD) simulations of solid P3HT with different molecular weights including calculation of structural parameters, mass density, melting temperature, glass transition temperature, and surface tension. At 300 K, the P3HT crystalline structure features planar backbones with non-interdigitated all-trans hexyl side chains twisted ~90° from the plane of the backbone.