Ion beam degradation analysis of poly(3-hexylthiophene) (P3HT): can cryo-FIB minimize irradiation damage?

Sezen, Meltem; Plank, Harald; Nellen, Philipp M.; Meier, Stephan; Chernev, Boril Stefanov; Grogger, Werner; Fisslthaler, Evelin; List, Emil; Scherf, Ullrich; Poelt, Peter

doi:10.1039/b816893h

Cited by 12 publications

(12 citation statements)

References 12 publications

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“…The effective electron dose at 5 keV, which is necessary to reduce the EBIC current by a factor of two in P3HT:PCBM solar cells, was 10 µC/cm 2 . The solar cell operation is much more sensitive to e‐beam damage compared to electron doses in e‐beam degradation studies, which induce a change in the surface potential by a similar amount (Sezen et al ., 2009). For this paper we chose solar cells with different defects to present the possibilities to detect them with EBIC measurements.…”

Section: Discussionmentioning

confidence: 99%

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Electron Beam‐Induced Current (EBIC) in solution‐processed solar cells

et al. 2011

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Electron Beam-Induced Current (EBIC) measurements were used to produce 2D maps for investigating the homogeneity of solar cells. These maps are acquired by scanning the electron beam of a scanning electron microscope over a small area and using a programmable sample stage to move the solar cell under the scan area. The electron beam generates electron-hole pairs in the solar cell much like light does in normal solar cell operation. Solution-processed solar cells where the active layer consisted of purely inorganic or purely organic materials were measured. Since the electron beam irreversibly damages organic material, it was important to ensure that the measurements were made before the materials were altered.

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Section: Discussionmentioning

confidence: 99%

“…This dose is lower than what is used to expose a resist in electron beam lithography. It is also a factor of 100 times lower than the electron dose at 5 keV needed to reduce the surface potential by a similar amount in studies of e‐beam damage to P3HT films (Sezen et al ., 2009).…”

Section: Ebic Experimentsmentioning

confidence: 99%

Electron Beam‐Induced Current (EBIC) in solution‐processed solar cells

et al. 2011

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“…Likewise, beam damage on delicate matter can produce artifacts and sample damage (Allison et al, 2010; Imai et al, 2003; Peckys et al, 2011). This can be delayed by using a low temperature sample stage, which, however, requires special equipment for a rapid sample freezing in order to prevent ice formation within the specimen (Clegg and Collyer, 1991; Sezen et al, 2009, 2011). Finally, the lack of capability to visualize dynamic processes and the non‐environmental conditions required (i.e., vacuum) further limits the application of TEM in following the structural dynamics of enzymatic cellulose degradation.…”

Section: Visualization Methods Applicable To Enzymatic Cellulose Hydrmentioning

confidence: 99%

Visualizing cellulase activity

Bubner

Plank

Nidetzky

2013

Biotech & Bioengineering

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Commercial exploitation of lignocellulose for biotechnological production of fuels and commodity chemicals requires efficient-usually enzymatic-saccharification of the highly recalcitrant insoluble substrate. A key characteristic of cellulose conversion is that the actual hydrolysis of the polysaccharide chains is intrinsically entangled with physical disruption of substrate morphology and structure. This "substrate deconstruction" by cellulase activity is a slow, yet markedly dynamic process that occurs at different length scales from and above the nanometer range. Little is currently known about the role of progressive substrate deconstruction on hydrolysis efficiency. Application of advanced visualization techniques to the characterization of enzymatic degradation of different celluloses has provided important new insights, at the requisite nano-scale resolution and down to the level of single enzyme molecules, into cellulase activity on the cellulose surface. Using true in situ imaging, dynamic features of enzyme action and substrate deconstruction were portrayed at different morphological levels of the cellulose, thus providing new suggestions and interpretations of rate-determining factors. Here, we review the milestones achieved through visualization, the methods which significantly promoted the field, compare suitable (model) substrates, and identify limiting factors, challenges and future tasks.

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“…The authors have recently been using this technique for the production of free‐standing polystyrene–platinum bimorph cantilever thermal microactuators for MEMS/NEMS applications (Lee et al ., 2011). These applications may, however, be limited by the creation of unwanted morphological and chemical modifications in the polymers due to variations in the surface structure of the polymer film (Ektessabi & Sano, 2000; Niihara et al ., 2005; Sezen et al ., 2009; Kim et al ., 2011; Sezen et al ., 2011). Critical issues in polymer micro/nanofabrication using the ion beam include direct sputtering and indirect thermal evaporation of surface atoms/molecules, depletion of main components of the polymer such as carbon, hydrogen, oxygen, etc., rearrangement of chemical bonds and cross‐linking, and incorporation of ions into the film (Ektessabi & Sano, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Possible routes to minimize the damage caused by the ion beam include milling the polymers at cryogenic temperatures (e.g. −150°C) to reduce local heating (Niihara et al ., 2005; Sezen et al ., 2009; Kim et al ., 2011; Sezen et al ., 2011), applying an electrically conductive coating or using an electron flood gun against ion charging (Stokes et al ., 2007) or removing the polymer at a faster rate using water vapour (Kochumalayil et al ., 2009a, b).…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional nanofabrication of polystyrene by focused ion beam

Lee

Proust

Alici

et al. 2012

Journal of Microscopy

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SummaryFocused ion beam micromachining provides a maskless and resistless technique for prototyping of structures from thermoplastic polymers, an example being the production of polystyrene microcantilevers with potential applications as micro/nanoelectromechanical systems sensors and actuators. The applicability of FIB technology is, however, often restricted by the damage created by high energy gallium ion bombardment and local beam heating, which can affect the desired properties and limit the minimum achievable size of the fabricated structure. To investigate the ion-induced damage and determine the limitations of the technique for polymer nanofabrication, we have exposed thin polystyrene film to the ion beam at varying ion doses, ion energies and specimen temperatures. Ion doses ranging from 10 16 to 10 18 ions cm −2 show significant gallium implantation, redeposition of sputtered material and chemical degradation in the polymer. Raman results show that the local heating in polymer during milling is severe at room temperature, damaging the aromatic carbon bonding (C = C) in particular. These observations are supported by the results of a beam heating model and Monte Carlo simulations. The chemical degradation caused by local beam heating is found to be significantly reduced by cooling the specimen to −25 • C during milling. This is consistent with observations that reversible and repeatable thermal actuation of a fabricated polystyrene-platinum microcantilever is only observed when the cantilever is prepared at low temperature milling. Using this cooling approach, polymer structures can be fabricated with dimensions as low as 200 nm and still retain a sufficient volume of material unaffected by the ion beam.

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Ion beam degradation analysis of poly(3-hexylthiophene) (P3HT): can cryo-FIB minimize irradiation damage?

Cited by 12 publications

References 12 publications

Electron Beam‐Induced Current (EBIC) in solution‐processed solar cells

Electron Beam‐Induced Current (EBIC) in solution‐processed solar cells

Visualizing cellulase activity

Three‐dimensional nanofabrication of polystyrene by focused ion beam

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