Substrate steered crystallization of naphthyl end-capped oligothiophenes into nanofibers: the influence of methoxy-functionalization

Vacuum deposition of the methoxy functionalized para-quaterphenylene MOP4 on muscovite mica at elevated temperatures leads to the formation of several ten micrometer long nanofibers. As shown by X-ray diffraction and by polarized optical microscopy, the fibers are formed by lying molecules, which grow epitaxially (point-on-line coincidence) along two directions on a single muscovite domain. The crystal structure of the fibers is induced by the substrate. Molecular packing is calculated by molecular dynamics simulations. A wetting layer from lying molecules is observed by low energy electron diffraction (LEED), with a different crystal structure from that of the fibers.Transfer of the sample from vacuum to ambient conditions leads to dewetting and to the formation of clusters from lying molecules. Samples age via Ostwald ripening due to the presence of water vapor, monitored by atomic force microscopy (AFM). Fibers represent chiral organization into single-handed aggregates of both handednesses, which is not affected by aging. On a global level the sample remains achiral.

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“…Similar effects have been observed for, e.g., naphthyl end-capped thiophenes 23,49 and para-hexaphenylene 71,72 .…”

Section: Acs Paragon Plus Environmentsupporting

confidence: 64%

Thin Film Phase and Local Chirality of Surface-Bound MOP4 Nanofibers

et al. 2016

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“…The series

(n = 0, 1, \dots, 72)

of images was analysed in ImageJ by a discrete Fourier transform

{\overset{I}{true}}_{2} (x, y) = \frac{1}{N} \sum_{n = 0}^{N - 1} I_{n}^{x, y} e^{- i 4 π n / N}

to determine from the intensity variation

I^{x, y}

of the pixel at position

(x, y)

the angle for the largest reflectivity or transmission. This angle was extracted using

ϕ_{1 pol, max} (x, y) = - \frac{1}{2} arg ({\overset{I}{true}}_{2} (x, y))

…”

Section: Methodsmentioning

confidence: 99%

Nanoscale Polarization‐Resolved Surface Photovoltage of a Pleochroic Squaraine Thin Film

Balzer

Abdullaeva

Maderitsch

et al. 2019

Physica Status Solidi (b)

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Local polarized surface photovoltage (SPV) spectroscopy is used to characterize an organic squaraine‐fullerene photovoltaic layer blend. The anisotropic optical response of the textured photoactive layer is dominated by the largely Davydov‐split absorption within the deep red of the crystallized donor compound. Through knowledge of the crystallographic texture, the local molecular in‐plane orientation is deduced. Kelvin probe force microscopy (KPFM) maps the differential SPV of the active layer on the nanoscale without complications by interfaces, which is spatially correlated with the pleochroic optical response of the thin film. The SPV shows a wavelength‐dependent, bichromatic change upon rotating the polarization axis of the illuminating light. With that subtler, nanoscaled optoelectronic sensing or actuating platforms become possible.

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“…Future studies should expand these experiments to Na2T nanofibers [23] and other naphtyl substituted oligothiophenes and surface effects as shown elsewhere for α, ω-dihexylsexithiophenes and other materials [16,38]. They may also benefit from reflectivity experiments as demonstrated for polythiophenes elsewhere [39].…”

Section: Time (H)mentioning

confidence: 99%

“…Among these materials, the crystal growth of 5,5'-bis(naphth-2-yl)-2,2'-bithiophene (NaT2) shows also a peculiar property as the molecules may form extremely high aspect ratio fibers, 20 nm thick and several micrometers long, when grown on muscovite mica, with potential in phototransistors [22] and waveguides [23]. Structures of these materials were characterized in the single crystal bulk but not in OFETs [21].…”

Section: Introductionmentioning

confidence: 99%

Structural stability of naphthyl end-capped oligothiophenes in organic field-effect transistors measured by grazing-incidence X-ray diffraction in operando

Huss-Hansen

Lauritzen

Bikondoa

et al. 2017

Organic Electronics

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. (2017) Structural stability of naphthyl end-capped oligothiophenes in organic field-effect transistors measured by grazingincidence X-ray diffraction in operando. Organic Electronics. Permanent WRAP URL:http://wrap.warwick.ac.uk/89989 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. AbstractWe report on microstructural durability of 5,5'-bis(naphth-2-yl)-2,2'-bithiophene (NaT2) in organic field effect transistors (OFETs) in operando monitored by grazing-incidence X-ray diffraction (GIXRD). NaT2 maintains its monoclinic bulk motif in operating OFETs with a = 20.31 ± 0.06Å, b = 6.00 ± 0.01Å, c = 8.17 ± 0.04Å and β = (96.64 ± 0.74)• . Crystallites appear as a mosaic of single crystals reaching through the whole 50 nm thick active layer. The lattice parameters variation (<1%) falls within the statistical error of structure refinement when the OFET gate voltage is varied from 0 V to -40 V; or when the OFET is continuously cycled within this voltage interval over more than 10 h period. Within the first few cycles, both the hole mobility and threshold voltage are changing but then reach stable levels with an average mobility of (3.25 ± 0.04) × 10 −4 cm 2 /Vs and an average threshold voltage of −13.6 ± 0.2 V, both varying less than 4% for the remainder of the 10 h period. This demonstrates crystalline stability of NaT2 in operating OFETs.

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Substrate steered crystallization of naphthyl end-capped oligothiophenes into nanofibers: the influence of methoxy-functionalization

Cited by 32 publications

References 68 publications

Thin Film Phase and Local Chirality of Surface-Bound MOP4 Nanofibers

Thin Film Phase and Local Chirality of Surface-Bound MOP4 Nanofibers

Nanoscale Polarization‐Resolved Surface Photovoltage of a Pleochroic Squaraine Thin Film

Structural stability of naphthyl end-capped oligothiophenes in organic field-effect transistors measured by grazing-incidence X-ray diffraction in operando

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