5 research outputs found
Photovoltaic performance of an ultrasmall band gap polymer
A conjugated polymer (PBTTQ) that consists of alternating electron-rich bithiophene and electron-deficient thiadiazoloquinoxaline units was synthesized via Yamamoto polymerization with Ni(cod)(2) and provides a band gap of 0.94 eV. This represents one of the smallest band gaps obtained for a soluble conjugated polymer. When applied in a bulk heterojunction solar cell together with [84]PCBM as the electron acceptor, the polymer affords a response up to 1.3 mu m
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Effects of OddâEven Side Chain Length of Alkyl-Substituted Diphenylbithiophenes on First Monolayer Thin Film Packing Structure
Because of their preferential two-dimensional layer-by-layer growth in thin films, 5,5âČbis(4-alkylphenyl)-2,2âČ-bithiophenes (P2TPs) are model compounds for studying the effects of systematic chemical structure variations on thin-film structure and morphology, which in turn, impact the charge transport in organic field-effect transistors. For the first time, we observed, by grazing incidence X-ray diffraction (GIXD), a strong change in molecular tilt angle in a monolayer of P2TP, depending on whether the alkyl chain on the P2TP molecules was of odd or even length. The monolayers were deposited on densely packed ultrasmooth self-assembled alkane silane modified surfaces. Our work shows that a subtle change in molecular structure can have a significant impact on the molecular packing structure in thin film, which in turn, will have a strong impact on charge transport of organic semiconductors. This was verified by quantum-chemical calculations that predict a corresponding oddâeven effect in the strength of the intermolecular electronic coupling.Chemistry and Chemical BiologyEngineering and Applied Science
Effects of OddâEven Side Chain Length of Alkyl-Substituted Diphenylbithiophenes on First Monolayer Thin Film Packing Structure
Effects of OddâEven Side Chain Length of Alkyl-Substituted Diphenylbithiophenes on First Monolayer Thin Film Packing Structure
Because
of their preferential two-dimensional layer-by-layer growth
in thin films, 5,5âČbisÂ(4-alkylphenyl)-2,2âČ-bithiophenes
(P2TPs) are model compounds for studying the effects of systematic
chemical structure variations on thin-film structure and morphology,
which in turn, impact the charge transport in organic field-effect
transistors. For the first time, we observed, by grazing incidence
X-ray diffraction (GIXD), a strong change in molecular tilt angle
in a monolayer of P2TP,
depending on whether the alkyl chain on the P2TP molecules was of
odd or even length. The monolayers were deposited on densely packed
ultrasmooth
self-assembled alkane silane modified SiO<sub>2</sub> surfaces.
Our work shows that a subtle change in molecular structure can have
a significant impact on the molecular packing structure in thin film,
which in turn, will have a strong impact on charge transport of organic
semiconductors. This was verified by quantum-chemical calculations
that predict a corresponding oddâeven effect in the strength
of the intermolecular electronic coupling