| 1. |
- Belgardt, Christian, et al.
(författare)
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Inkjet printing as a tool for the patterned deposition of octadecylsiloxane monolayers on silicon oxide surfaces
- 2013
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:20, s. 7494-504
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Tidskriftsartikel (refereegranskat)abstract
- We present a case study about inkjet printing as a tool for molecular patterning of silicon oxide surfaces with hydrophobic functionality, mediated by n-octadecyltrichlorosilane (OTS) molecules. In contrast to state-of-the-art techniques such as micro contact printing or chemical immersion with subsequent lithography processes, piezo drop-on-demand inkjet printing does not depend on physical masters, which allows an effective direct-write patterning of rigid or flexible substrates and enables short run-lengths of the individual pattern. In this paper, we used mesithylene-based OTS inks, jetted them in droplets of 10 pL on a silicon oxide surface, evaluated the water contact angle of the patterned areas and fitted the results with Cassie's law. For inks of 2.0 mM OTS concentration, we found that effective area coverages of 38% can be obtained. Our results hence show that contact times of the order of hundred milliseconds are sufficient to form a pattern of regions with OTS molecules adsorbed to the surface, representing at least a fragmented, inhomogeneous self-assembled OTS monolayer (OTS-SAM).
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| 2. |
- Belgardt, Christian, et al.
(författare)
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Self-Assembly of Ordered Colloidal Nanoparticle Films in Few-Micron Wide Laser-Desorbed Lines of Octadecylsiloxane Monolayers on Silicon Oxide Surfaces
- 2014
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Ingår i: Advanced Engineering Materials. - : Wiley-VCH Verlag. - 1438-1656 .- 1527-2648. ; 16:9, s. 1090-1097
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Tidskriftsartikel (refereegranskat)abstract
- We report about a maskless technique to deposit colloidal polystyrene particles in patterned stripes with a line width as narrow as 1.5m. Our approach is based on the digital patterning of a hydrophobic octadecylsiloxane self-assembled monolayer (SAM) on a silicon oxide surface by laser-assisted decomposition and desorption of its organic parts. For hydrophilic stripes of the micropatterned SAM area down to widths of approximately 1.5m, we observed ordered, mainly monolayered stripes of colloidal polystyrene nanoparticles using a modified vertical deposition technique, dipping the silicon substrate into a colloidal suspension at an angle of around 45 degrees with respect to the surface normal of the liquid. The mechanism of this so-called slope self-assembly [Wu et al., Langmuir2013, 29, 14017] and its limitations with respect to stacking can be explained in the framework of a meniscus moving along the steps of alternating surface energy with the decreasing width of the hydrophilic stripes during the deposition process [Fustin et al., Langmuir2004, 20, 9114].
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| 3. |
- Blaudeck, Thomas, et al.
(författare)
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Biocomputation Using Molecular Agents Moving in Microfluidic Channel Networks : An Alternative Platform for Information Technology
- 2022
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Ingår i: Cyber-Physical Systems : Intelligent Models and Algorithms - Intelligent Models and Algorithms. - Cham : Springer International Publishing. - 2198-4190 .- 2198-4182. - 9783030951153 - 9783030951160 ; 417, s. 15-27
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Bokkapitel (refereegranskat)abstract
- Deficiencies in software or computer chips cause computers or smartphones to crash and allow hackers to steal passwords. Automated test procedures could avoid these problems. However, the computing power and cooling requirements of conventional computers increase exponentially with the size of the problem, so that the technological limits for solving these problems will soon be reached. The EU project Bio4Comp aims to develop concepts for a bio-computer to help overcome these two main problems. Compared to conventional computers, computers based on biological molecular motors only consume a fraction of the energy per arithmetic operation and scale very well for problems that can be parallelized (“multitasking”). In this article, the topic network-based biocomputation (NBC) i.e. computing with biological molecules as agents that are driven by molecular motors in microfluidic networks, is presented as an alternative approach to computing, data processing, and information technology.
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| 4. |
- Blaudeck, Thomas, et al.
(författare)
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Formation Principles and Ligand Dynamics of Nanoassemblies of CdSe Quantum Dots and Functionalised Dye Molecules
- 2012
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Ingår i: ChemPhysChem. - : Wiley-Blackwell / Wiley-VCH Verlag Berlin. - 1439-4235 .- 1439-7641. ; 13:4, s. 959-972
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Tidskriftsartikel (refereegranskat)abstract
- Functional dye molecules, such as porphyrins, attached to CdSe quantum dots (QDs) through anchoring meso-pyridyl substituents, form quasi-stable nanoassemblies. This fact results in photoluminescence (PL) quenching of the QDs both due to Forster resonance energy transfer (FRET) and the formation of non-radiative surface states under conditions of quantum confinement (non-FRET). The formation process is in competition with the ligand dynamics. At least two timescales are found for the formation of the assemblies: 1) one faster than 60 s attributed to saturation of empty attachment sites and 2) one slower than 600 s, which is attributed to a reorganisation of the tri-n-octylphosphine oxide (TOPO) ligand shell. Finally, this process results in almost complete exchange of the TOPO shell by porphyrin dye molecules. Following a SternVolmer analysis, we established a microscopic description of PL quenching and assembly formation. Based on this formalism, we determined the equilibrium constant for assembly formation between QDs and the pyridyl-functionalised dye molecules to be K approximate to 10(5)-10(7) M-1, which is several orders of magnitude larger than that of the TOPO ligands. Our results give additional insights into the non-FRET PL quenching processes involved and show that the QD surface is inhomogeneous with respect to the involved attachment and detachment processes. In comparison with other methods, such as NMR spectroscopy, the advantage of our approach is that ligand dynamics can be investigated at extremely low ratios of dye molecules to QDs.
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| 5. |
- Blaudeck, Thomas, et al.
(författare)
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Simplified Large-Area Manufacturing of Organic Electrochemical Transistors Combining Printing and a Self-Aligning Laser Ablation Step
- 2012
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Ingår i: Advanced Functional Materials. - : Wiley-VCH Verlag Berlin. - 1616-301X .- 1616-3028. ; 22:14, s. 2939-2948
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid manufacturing approach for organic electrochemical transistors (OECTs) on flexible substrates is reported. The technology is based on conventional and digital printing (screen and inkjet printing), laser processing, and post-press technologies. A careful selection of the conductive, dielectric, and semiconductor materials with respect to their optical properties enables a self-aligning pattern formation which results in a significant reduction of the usual registration problems during manufacturing. For the prototype OECTs, based on this technology, on/off ratios up to 600 and switching times of 100 milliseconds at gate voltages in the range of 1 V were obtained.
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| 6. |
- Meinecke, Christoph R., et al.
(författare)
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Nanolithographic Fabrication Technologies for Network-Based Biocomputation Devices
- 2023
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Ingår i: Materials. - : MDPI. - 1996-1944. ; 16:3
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Tidskriftsartikel (refereegranskat)abstract
- Network-based biocomputation (NBC) relies on accurate guiding of biological agents through nanofabricated channels produced by lithographic patterning techniques. Here, we report on the large-scale, wafer-level fabrication of optimized microfluidic channel networks (NBC networks) using electron-beam lithography as the central method. To confirm the functionality of these NBC networks, we solve an instance of a classical non-deterministic-polynomial-time complete ("NP-complete") problem, the subset-sum problem. The propagation of cytoskeletal filaments, e.g., molecular motor-propelled microtubules or actin filaments, relies on a combination of physical and chemical guiding along the channels of an NBC network. Therefore, the nanofabricated channels have to fulfill specific requirements with respect to the biochemical treatment as well as the geometrical confienement, with walls surrounding the floors where functional molecular motors attach. We show how the material stack used for the NBC network can be optimized so that the motor-proteins attach themselves in functional form only to the floor of the channels. Further optimizations in the nanolithographic fabrication processes greatly improve the smoothness of the channel walls and floors, while optimizations in motor-protein expression and purification improve the activity of the motor proteins, and therefore, the motility of the filaments. Together, these optimizations provide us with the opportunity to increase the reliability of our NBC devices. In the future, we expect that these nanolithographic fabrication technologies will enable production of large-scale NBC networks intended to solve substantially larger combinatorial problems that are currently outside the capabilities of conventional software-based solvers.
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| 7. |
- Trong Dinh, Nghia, et al.
(författare)
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High-resolution inkjet printing of conductive carbon nanotube twin lines utilizing evaporation-driven self-assembly
- 2016
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Ingår i: Carbon. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0008-6223 .- 1873-3891. ; 96, s. 382-393
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Tidskriftsartikel (refereegranskat)abstract
- We report about the inkjet printing of multi-walled carbon nanotubes (MWCNTs) for conductive tracks. The MWCNTs were grown by chemical vapor deposition allowing a defined length and diameter. An inkjet-printable ink formulation was prepared by dispersing the MWCNTs in water. Inkjet-printed high resolution patterns were obtained by printing the prepared ink formulation on silicon wafers utilizing evaporation-driven self-assembly processes. After the deposition of the ink, the solvent evaporation induces material flows within the liquid moving the MWCNTs preferably to the edges of the printed patterns as well as to the print starting position where they assemble. Atomic force microscopy (AFM) reveals a preferential orientation of the deposited MWCNTs. The resulting deposit pattern is well-known as coffee-ring effect which is used here to enable high resolution printing and self-ordering of the MWCNTs. Depending on different print parameters such as drop spacing or substrate temperature, conductive track widths in the range of 5-15 mu m were achieved with a electrical resistivity of about 3.9.10(-3) to 5.6.10(-3) Omega.m measured by current-sensitive AFM. (C) 2015 Elsevier Ltd. All rights reserved.
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| 8. |
- van Delft, Falco C. M. J. M., et al.
(författare)
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Roadmap for network-based biocomputation
- 2022
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Ingår i: Nano Futures. - : Institute of Physics Publishing (IOPP). - 2399-1984. ; 6:3
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Forskningsöversikt (refereegranskat)abstract
- Network-based biocomputation (NBC) is an alternative, parallel computation approach that can potentially solve technologically important, combinatorial problems with much lower energy consumption than electronic processors. In NBC, a combinatorial problem is encoded into a physical, nanofabricated network. The problem is solved by biological agents (such as cytoskeletal filaments driven by molecular motors) that explore all possible pathways through the network in a massively parallel and highly energy-efficient manner. Whereas there is currently a rapid development in the size and types of problems that can be solved by NBC in proof-of-principle experiments, significant challenges still need to be overcome before NBC can be scaled up to fill a technological niche and reach an industrial level of manufacturing. Here, we provide a roadmap that identifies key scientific and technological needs. Specifically, we identify technology benchmarks that need to be reached or overcome, as well as possible solutions for how to achieve this. These include methods for large-scale production of nanoscale physical networks, for dynamically changing pathways in these networks, for encoding information onto biological agents, for single-molecule readout technology, as well as the integration of each of these approaches in large-scale production. We also introduce figures of merit that help analyze the scalability of various types of NBC networks and we use these to evaluate scenarios for major technological impact of NBC. A major milestone for NBC will be to increase parallelization to a point where the technology is able to outperform the current run time of electronic processors. If this can be achieved, NBC would offer a drastic advantage in terms of orders of magnitude lower energy consumption. In addition, the fundamentally different architecture of NBC compared to conventional electronic computers may make it more advantageous to use NBC to solve certain types of problems and instances that are easy to parallelize. To achieve these objectives, the purpose of this roadmap is to identify pre-competitive research domains, enabling cooperation between industry, institutes, and universities for sharing research and development efforts and reducing development cost and time.
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| 9. |
- Zenkevich, Eduard I, et al.
(författare)
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Quantitative Analysis of Singlet Oxygen ((1)O(2)) Generation via Energy Transfer in Nanocomposites Based on Semiconductor Quantum Dots and Porphyrin Ligands
- 2011
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society. - 1932-7447 .- 1932-7455. ; 115:44, s. 21535-21545
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Tidskriftsartikel (refereegranskat)abstract
- We report on the results of a detailed quantitative experimental exciton relaxation pathways as well as direct measurement of singlet oxygen ((1)O(2)) generation efficiencies for CdSe/ZnS quantum dot (QD)- porphyrin nanocomposites in toluene at 295 K QD photoluminescence. quenching in nanocomposites is caused. by two main factors: electron tunneling in the quantum confined QD.(efficiency 0.85-0.90) and Forster resonance energy transfer (FRET) QD -andgt; porphyrin (quenching efficiency 0.10-0.15). Efficiencies of (1)O(2) generation gamma(Delta) by nanocomposites are essentially higher with respect to those obtained for QDs alone. For nanocomposites, the nonlinear decrease of (1)O(2) generation efficiency gamma(Delta) on the laser pulse energy is caused by nonradiative intraband Auger processes, realized in the QD counterpart. Finally, FRET efficiencies found from the direct sensitization data for porphyrin fluorescence in, nanocomposites (Phi(FRET) = 0.14 +/- 0.02) are in good agreement with the corresponding values obtained via the direct (1)O(2) generation measurements at low laser excitation (Phi(Delta)(FRET) = 0.12 +/- 0.03). The obtained quantitative results provide for the first time strong evidence that a FRET process QD -andgt; porphyrin is the reason for singlet oxygen generation by nanocomposites.
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| 10. |
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