المؤلفون: PROOTH, Jeroen, PETROV, Michael, SHMAKOVA, Alevtina, GULKA, Michal, Cigler, Petr, D'HAEN, Jan, BOYEN, Hans-Gerd, NESLADEK, Milos

المساهمون: PROOTH, Jeroen, PETROV, Michael, SHMAKOVA, Alevtina, GULKA, Michal, Cigler, Petr, D'HAEN, Jan, BOYEN, Hans-Gerd, NESLADEK, Milos

مصطلحات موضوعية: chemical vapor deposition, fluorescent nanodiamonds, nitrogen-vacancy (NV) spin relaxometry, quantum sensing

الوصف: Currently, the primary applications of fluorescent nanodiamonds (FNDs) are in the area of biosensing, by using photoluminescence or spin properties of color centres, mainly represented by the nitrogen vacancy (NV) point defect. The sensitivity of NV-FNDs to external fields is, however, limited by crystallographic defects, which influence their key quantum state characteristics - the spin longitudinal (T1) and spin transversal (T2) relaxation and coherence times, respectively. This paper reports on utilizing an advanced FND growth technique consisting of heterogeneous nucleation on pre-engineered sites to create FNDs averaging around 60 nm in size, with mean longitudinal coherence times of 800 mu$\umu$s and a maximum over 1.8 ms, close to bulk theoretical values. This is a major, nearly ten-fold improvement over commercially available nanodiamonds for the same size range of 50 to 150 nm. Heavy-N doped nanodiamond shells, important for sensing events in nm proximity to the diamond surface, are fabricated and discussed in terms of re-nucleation and twinning on {111} crystal facets. The scalability issues are discussed in order to enable the production of FND volumes matching the needs of sensing applications. ; J.P. and M.P. contributed equally to this work. The author would like to acknowledge the following projects: Diamond for chip-based quantum detection in bioelectrode multi-electrode recordings of human iPSCderived neurons and axonal networks (R-11434), i-BOF; EU Quantera II Project Maestro; EU Horizon 2020 project Amadeus grant agreements ID: 101080136 and No. 101046911 QuMicro. M.G. acknowledges the Eu project No. 101038045 (ChemiQS): This Project has received funding from the European Union’s Horizon 2020 research and innovation programme. The work was also supported by the Czech Science Foundation projects no. 23-04876S and No. 20-28980s, the European Regional Development Funds, OP RDE, Project: CARAT (No. CZ.02.1.01/0.0/0.0/16_026/0008382), and by the Czech Academy of Sciences - Strategy AV21 - Research ...

وصف الملف: application/pdf

العلاقة: info:eu-repo/grantAgreement/EC/H2020/101080136; Advanced Quantum Technologies, 6 (12), (Art N° 2300004); http://hdl.handle.net/1942/41808Test; 12; 001086207300001

الإتاحة: https://doi.org/10.1002/qute.202300004Test
http://hdl.handle.net/1942/41808Test

المؤلفون: Devisscher, Dries, Reekmans, Gunter, Kesters, Jurgen, Verstappen, Pieter, Benduhn, Johannes, Van den Brande, Niko, Lutsen, Laurence, Manca, Jean, Vanderzande, Dirk, Vandewal, Koen, Adriaensens, Peter, Maes, Wouter

مصطلحات موضوعية: Push-pull copolymers, Side chain variation, Blend morphology, Solid-state NMR relaxometry, External quantum efficiency

الوصف: A significant number of organic electronic devices rely on blends of electron-donating and electron-accepting molecules. In bulk heterojunction organic photovoltaics, the nanoscopic phase behavior of the two individual components within the photoactive layer has a major impact on the charge separation and charge transport properties. For polymer:fullerene solar cells, it has been hypothesized that an increased accessibility of the electron-deficient monomer unit in push-pull type low bandgap polymers allows for fullerene ‘docking’. The close proximity of electron donor and acceptor molecules enables more efficient charge transfer, which is beneficial for the device efficiency. With this in mind, we synthesized a series of PBDTTPD [poly(benzodithiophene-thienopyrroledione)] low bandgap copolymers with varying side chains. Solar cells were fabricated for all polymers and the device characteristics were compared. The combination of proton wideline solid-state NMR (ssNMR) relaxometry and sensitive external quantum efficiency (sEQE) measurements was shown to provide essential information on donor-acceptor interactions and phase separation in bulk heterojunction organic photovoltaics. The reduced charge transfer state absorption and the observed phase separation of crystalline PC71BM domains for the polymers containing the most accessible methyl-TPD unit indicate a diminished contact between donor and acceptor, leading to a loss in performance. ; This work is supported by Hasselt University and the Research Foundation Flanders (FWO Vlaanderen; project G.0B27.18N).

وصف الملف: application/pdf

العلاقة: ORGANIC ELECTRONICS, 74, p. 309-314; http://hdl.handle.net/1942/29634Test; 314; 309; 74; 000485015600044; https://www.sciencedirect.com/science/article/pii/S1566119919303416Test

الإتاحة: https://doi.org/10.1016/j.orgel.2019.06.046Test
http://hdl.handle.net/1942/29634Test
https://www.sciencedirect.com/science/article/pii/S1566119919303416Test

المؤلفون: ADRIAENSENS, Peter, ROEX, Hilde, VANDERZANDE, Dirk, GELAN, Jan

مصطلحات موضوعية: conjugated polymers, NMR relaxometry, thermal elimination

الوصف: A sensitive protocol to judge the completeness of the elimination reaction for soluble and insoluble conjugated polymers prepared via precursor routes is presented based on UV/vis and H-1 wideline NMR relaxometry in the solid state. Especially the proton spin-lattice decay time in the rotating frame, T-1pH, has proven to be suitable for an accurate determination of the completeness of the elimination reaction. Especially for long side-chain substituted PPV derivatives, UV/vis seems to be limited due to thermochromic effects. Furthermore, it is shown by solid state 2 H wideline NMR spectroscopy that incomplete elimination results in an enhanced polymer backbone chain mobility. Both the completeness of elimination and insight into the molecular dynamics can be of significant importance toward the performance of photovoltaic devices. (C) 2004 Elsevier Ltd. All rights reserved.

العلاقة: POLYMER, 46(6). p. 1759-1765; http://hdl.handle.net/1942/2163Test; 1765; 1759; 46; 000227246200006

الإتاحة: https://doi.org/10.1016/j.polymer.2004.12.029Test
http://hdl.handle.net/1942/2163Test

المؤلفون: ADRIAENSENS, Peter, POLLARIS, Anne, Rulkens, R, Litvinov, VM, GELAN, Jan

مصطلحات موضوعية: MRI, relaxometry, PA46 copolymers

الوصف: Magnetic resonance imaging (MRI), NMR relaxometry, thermal analysis and gravimetrical experiments are performed to study the water absorption by neat PA46 and copolymers of PA46 and PA4n (PA46-co-PA4n) with 4 mol% n = 8, 12 and 16. The observed reduction in water uptake, ingress rate and water molecular mobility with increasing value of n is explained by a combination of several physico-chemical molecular properties. The increased [CH2]/[amide] ratio and the reduced amount of crystallinity do not completely clarify the observed trends in water uptake and water molecular mobility in the copolymer series. It is shown that the increased chain mobility of the PA46 segments in the copolymers allows an improved coupling of the amide groups in the amorphous phase, explaining the observed decrease in water uptake. The important role of the morphology of the amorphous phase for water uptake is further demonstrated by annealing results and NMR relaxation experiments as a function of temperature. (C) 2004 Elsevier Ltd. All rights reserved.

العلاقة: POLYMER, 45(8). p. 2465-2473; http://hdl.handle.net/1942/2432Test; 2473; 2465; 45; 000220533500001

الإتاحة: https://doi.org/10.1016/j.polymer.2004.02.007Test
http://hdl.handle.net/1942/2432Test

المؤلفون: ADRIAENSENS, Peter, CARLEER, Robert, STORME, Liesbet, VANDERZANDE, Dirk, GELAN, Jan

مصطلحات موضوعية: poly(3,4-ethylenedioxythiophene), polystyrenesulfonic acid, C-13-CP/MAS NMR relaxometry

الوصف: The nanometer morphology of a mixture of the electrically conductive polymer poly(3,4-ethylenedioxythiophene) and polystyrene-sulfonic acid is studied by means of solid state C-13-CP/MAS NMR relaxation experiments. Based on the T1H and T1pH NMR relaxation decay times, determined via the chemical shift selective carbon resonances, it can be concluded that the mixture is homogeneous on the nanometer scale. Consequently, charge transport (hopping) between PEDT chains is hindered, resulting in antistatic properties. (C) 2002 Elsevier Science Ltd. All rights reserved.

العلاقة: POLYMER, 43(25). p. 7003-7006; http://hdl.handle.net/1942/2488Test; 7006; 25; 7003; 43; 000179075700040

الإتاحة: https://doi.org/10.1016/S0032-3861Test(02)00322-1
http://hdl.handle.net/1942/2488Test