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Item type:Publication, Access status: without files , Stretchable semiconducting triblock copolymer blends : exploring the impact of block size(2024-03-06); ; 27 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Synthesis of linear unsubstituted poly(4,4′-triphenylamine) via Suzuki-Miyaura coupling of an asymmetric AB monomer(2022-06-15); ; ; ; Polytriarylamines (PTAAs) are amorphous polymers that can be reversibly oxidized to generate stable radical cations. Despite exhibiting a low charge carrier mobility, PTAAs are widely used as hole-transporting layers in perovskite solar cells due to their excellent stability under ambient conditions. The highest occupied molecular orbital (HOMO) energy levels of PTAA are generally in the range of −5.1 to −5.2 eV, and therefore slightly too high for an optimal alignment with perovskites. Most linear PTAAs carry two or three methyl substituents per repeating unit. While these prevent crosslinking of chains and thus provide reaction control, the electron-donating substituents raise the energy level of the HOMO. Unsubstituted PTAA on the other hand is usually obtained crosslinked via oxidative polymerization, while nickel-catalyzed Grignard polycondensation leads to inclusion of impurities. We report the synthesis of linear unsubstituted PTAA using Suzuki-Miyaura coupling of a novel asymmetric monomer, 4-((4-bromophenyl)(phenyl)amino)phenyl)boronic acid M1. Based on matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) and 1H NMR analysis, we can conclude that the hydrogen-terminated linear polymer is obtained. The determined HOMO energy level of −5.47 eV is a favorable match for many perovskite systems.Publicationtype: Journal Article16 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Charge carrier mobility improvement in diketopyrrolopyrrole block‐copolymers by shear coating(2021-05-01); ; ; ; Shear coating is a promising deposition method for upscaling device fabrication and enabling high throughput, and is furthermore suitable for translating to roll‐to‐roll processing. Although common polymer semiconductors (PSCs) are solution processible, they are still prone to mechanical failure upon stretching, limiting applications in e.g., electronic skin and health monitoring. Progress made towards mechanically compliant PSCs, e.g., the incorporation of soft segments into the polymer backbone, could not only allow such applications, but also benefit advanced fabrication methods, like roll‐to‐roll printing on flexible substrates, to produce the targeted devices. Tri‐block copolymers (TBCs), consisting of an inner rigid semiconducting poly‐diketo‐pyrrolopyrrole‐thienothiophene (PDPP‐TT) block flanked by two soft elastomeric poly(dimethylsiloxane) (PDMS) chains, maintain good charge transport properties, while being mechanically soft and flexible. Potentially aiming at the fabrication of TBC‐based wearable electronics by means of cost‐efficient and scalable deposition methods (e.g., blade‐coating), a tolerance of the electrical performance of the TBCs to the shear speed was investigated. Herein, we demonstrate that such TBCs can be deposited at high shear speeds (film formation up to a speed of 10 mm s−1). While such high speeds result in increased film thickness, no degradation of the electrical performance was observed, as was frequently reported for polymer−based OFETs. Instead, high shear speeds even led to a small improvement in the electrical performance: mobility increased from 0.06 cm2 V−1 s−1 at 0.5 mm s−1 to 0.16 cm2 V−1 s−1 at 7 mm s−1 for the TBC with 24 wt% PDMS, and for the TBC containing 37 wt% PDMS from 0.05 cm2 V−1 s−1 at 0.5 mm s−1 to 0.13 cm2 V−1 s−1 at 7 mm s−1. Interestingly, the improvement of mobility is not accompanied by any significant changes in morphology.Publicationtype: Journal Article16 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Amorphous conjugated polymers as efficient dual-mode MALDI matrices for low-molecular-weight analytes(Wiley-VCH, 2019-06-18); ; ; ; Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) usually employs highly crystalline small-molecule matrices, and the analyte is interpreted as being co-crystallized with the matrix. We recently showed that semi-crystalline polymers are efficient matrices for the detection of low-molecular-weight compounds (LMWCs) in MALDI MS and MALDI MS Imaging, and are dual-mode, i. e., enabling both positive and negative modes. The matrix performances of two fluorene/napthalene diimide co-polymers P(TNDIT-Fl(C4C2)) and P(TNDIT-Fl(C10C8)) were investigated and compared. Both are fully amorphous according to XRD measurements, show high relative absorption values at the wavelength of common MALDI lasers (λNd:YAG=355 nm: C4C2=73 %; C10C8=67 %), and are solution processable. As matrices, they are dual-mode, and enable the detection of LMWCs while being mostly MALDI-silent. Compared with semicrystalline polymer matrices, the amorphous matrices give similar or better signal intensities, thus indicating that analyte inclusion takes place in the amorphous part of the polymer matrix.Publicationtype: Journal ArticleScopus© Citations 8 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Layer-by-layer assembly enabled by the anionic p-dopant CN6-CP•-K+: a route to achieve interfacial doping of organic semiconductorsHighly efficient 2D (interfacial) doping of organic semiconductors, poly(3-hexylthiophene) (P3HT) and TIPS-pentacene, was achieved by a polyelectrolyte-supported layer-by-layer assembly of the dual-mode functional dopant CN6-CP•-K+, having an anionic group for its fixation onto oppositely charged surfaces/molecules as well as electron-deficient groups providing its p-doping ability. Polyelectrolyte-supported dopant layers were used to generate conductive channels at the bottom or at the top of semiconducting films. Unlike to the case of sequentially processed P3HT films doped by F4TCNQ (Moulé, J. Chem. Mater. 2015, 27, 5765; Koech, P. K. J. Mater. Chem. C 2013, 1, 1876; Schwartz, B. J. J. Phys. Chem. Lett. 2015, 6, 4786), the use of more polar CN6-CP•-K+ dopant and ultrathin polycation separation interlayer enables predominantly interfacial kind of doping placement with no or minimal intercalation of the dopant into the semiconductor bulk. The layered structure of the doped film was proved by transmission electron microscopy of the cross-section and it agrees well with other data obtained in this work. The interfacial doping enabled an impressive conductivity of 13 S/cm even for ultrathin P3HT films. We propose to explain the superior efficiency of the interfacial doping compared to the bulk doping in terms of unperturbed morphology of the semiconductor and high mobility of charge carriers, which are spatially separated from the dopant phase.Publicationtype: Journal ArticleScopus© Citations 6 24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Conjugated Polymers as a New Class of Dual-Mode Matrices for MALDI Mass Spectrometry and Imaging(2018-09-12); ; ; ; Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and MALDI MS imaging are ubiquitous analytical methods in medical, pharmaceutical, biological, and environmental research. Currently, there is a strong interest in the investigation of low molecular weight compounds (LMWCs), especially to trace and understand metabolic pathways, requiring the development of new matrix systems that have favorable optical properties and a high ionization efficiency and that are MALDI silent in the LMWC area. In this paper, five conjugated polymers, poly[N,N'-bis(2-octyldodecyl)-naphtalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'(2,2'-bithiophene) (PNDI(T2)), poly(3-dodecylthiophene-2,5-diyl) (P3DDT), poly[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl]-alt-(thiophene-2,5-diyl) (PTQ1), poly[N,N'-bis(2-octyldodecyl)-isoindigo-5,5'-diyl]-alt-5,5'(2,2'-bithiophene) (PII(T2)), and poly(9,9-di-n-octylfluorenyl-2,7-diyl) (P9OFl) are investigated as matrices. The polymers have a strong optical absorption, are solution processable, and can be coated into thin films, allowing a vast reduction in the amount of matrix used. All investigated polymers function as matrices in both positive and negative mode MALDI, classifying them as rare dual-mode matrices, and show a very good analyte ionization ability in both modes. PNDI(T2), P3DDT, PTQ1, and PII(T2) are MALDI silent in the full measurement range (>m/z = 150k), except at high laser intensities. In MALDI MS experiments of single analytes and a complex biological sample, the performance of the polymers was found to be as good as two commonly used matrices (2,5-DHB for positive and 9AA for negative mode measurements). The detection limit of two standard analytes was determined as being below 164 pmol for reserpine and below 245 pmol for cholic acid. Additionally P3DDT was used successfully in first MALDI MS imaging experiments allowing the visualization of the tissue morphology of rat brain sections.Publicationtype: Journal ArticleScopus© Citations 41 16