Herein we present a molecular doping of a high mobility diketopyrrolopyrrole−dithienylthieno[3,2-b]thiophene donor−acceptor copolymer poly[3,6-thiophene], PDPP(6-DO) 2 TT, with the electron-deficient compound hexafluorotetracyanonaphthoquinodimethane (F6TCNNQ). Despite a slightly negative HOMO donor −LUMO acceptor offset of −0.12 eV which may suggest a reduced driving force for the charge transfer (CT), a partial charge CT was experimentally observed in PDPP(6-DO) 2 TT:F6TCNNQ by absorption, vibrational, and electron paramagnetic resonance spectroscopies and predicted by density functional theory calculations. Despite the modest CT, PDPP(6-DO) 2 TT:F6TCNNQ films possess unexpectedly high conductivities up to 2 S/cm (comparable with the conductivities of the benchmark doped polymer system P3HT:F4TCNQ having a large positive offset). The observation of the high conductivity in doped PDPP(6-DO) 2 TT films can be explained by a high hole mobility in PDPP(6-DO) 2 TT blends which compensates a lowered (relatively to P3HT:F4TCNQ) concentration of free charge carriers. We also show that F6TCNNQ-doped P3HT, the system which has not been reported so far to the best of our knowledge, exhibits a conductivity up to 7 S/cm, which exceeds the conductivity of the benchmark P3HT:F4TCNQ system.

Using coarse-grained DPD simulations, we study the morphology of AB diblock copolymer brushes in selective solvents which are good for the anchored A blocks but poor (of varying degrees measured by the distance from the Θ-point, τ B ) for B blocks. Choosing appropriate polymer compositions given by the fraction of B blocks, f B , we find transitions between spherical and cylindrical micelles as well as inverted morphologies (perforated layer). We discuss the phase diagram in the f B -τ B parameter space and analyze characteristic quantities of the structures obtained such as domain size, periodic spacing and brush height. The internal structure of the uniform (lamellar) structure is investigated in detail. The simulation results are compared with theoretical predictions and experimental observations.

In this work we apply a joint experimental and theoretical approach to investigate thin films of side chain substituted dicyanovinyl quaterthiophenes (DCV4T-Et2) and DCV4T-Et2:C60 blends, prototypic absorbers for small molecule organic solar cells. Structural characterization of the morphology of thin films thermally deposited at different substrate temperatures on a silica surface was performed by variable angle spectroscopic ellipsometry, grazing incidence X-ray diffraction, and atomic force microscopy measurements. These methods, combined with full-atomistic molecular dynamic (MD) simulation, provide detailed information about thin film morphology, namely about molecular orientation, absorption, phase separation, and crystallinity, i.e., factors that affect the efficiency of organic solar cells. Using molecular dynamics simulation, we can constitute why the DCV4T-Et2 molecules arrange strongly tilted in pristine (69°to 70°tilt angle to the substrate normal) and DCV4T-Et2:C60 blend films (tilt angle of 65°to 69°).

In this computational work, we investigate the photosensitive cationic surfactants with the trimethylammonium or polyamine hydrophilic head and the azobenzene-containing hydrophobic tail. The azobenzene-based molecules are known to undergo a reversible trans-cis-trans isomerization reaction when subjected to UV-visible light irradiation. Combining the density functional theory and the all-atom molecular dynamics simulations, the structural and the hydration properties of the trans- and the cis-isomers and their interaction with the oppositely charged poly(methacrylic acid) in aqueous solution are investigated. We establish and quantify the correlations of the molecular structure and the isomerization state of the surfactants and their hydrophilicity/hydrophobicity and the self-assembling altered by light. For this reason, we compare the hydration free energies of the trans- and the cis-isomers. Moreover, the investigations of the interaction strength between the azobenzene molecules and the polyanion provide additional elucidations of the recent experimental and theoretical studies on the light triggered reversible deformation behavior of the microgels and the polymer brushes loaded with azobenzene surfactants.