TY - GEN A1 - Wessig, Pablo A1 - John, Leonard A1 - Sperlich, Eric A1 - Kelling, Alexandra T1 - Sulfur tuning of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The replacement of oxygen by sulfur atoms of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes is an efficient way to adjust the photophysical properties (sulfur tuning). While previously developed S-4-DBD dyes exhibit considerably red-shifted absorption and emission wavelength, the heavy atom effect of four sulfur atoms cause low fluorescence quantum yields and short fluorescence lifetimes. Herein, we demonstrate that the replacement of less than four sulfur atoms (S-1-DBD, 1,2-S-2-DBD, and 1,4-S-2-DBD dyes) permits a fine-tuning of the photophysical properties. In some cases, a similar influence on the wavelength without the detrimental effect on the quantum yields and lifetimes is observed. Furthermore, the synthetic accessibility of S-1- and S-2-DBD dyes is improved, compared with S-4-DBD dyes. For coupling with biomolecules a series of reactive derivatives of the new dyes were developed (azides, OSu esters, alkynes, maleimides). T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1381 KW - fluorescent dyes KW - heterocycles KW - photophysics KW - stokes shift KW - sulfur Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-566241 SN - 1866-8372 IS - 3 ER - TY - THES A1 - Eren, Enis Oğuzhan T1 - Covalent anode materials for high-energy sodium-ion batteries T1 - Kovalente Anodenmaterialien für hoch-energetische Natrium-Ionen-Batterien N2 - The reliance on fossil fuels has resulted in an abnormal increase in the concentration of greenhouse gases, contributing to the global climate crisis. In response, a rapid transition to renewable energy sources has begun, particularly lithium-ion batteries, playing a crucial role in the green energy transformation. However, concerns regarding the availability and geopolitical implications of lithium have prompted the exploration of alternative rechargeable battery systems, such as sodium-ion batteries. Sodium is significantly abundant and more homogeneously distributed in the crust and seawater, making it easier and less expensive to extract than lithium. However, because of the mysterious nature of its components, sodium-ion batteries are not yet sufficiently advanced to take the place of lithium-ion batteries. Specifically, sodium exhibits a more metallic character and a larger ionic radius, resulting in a different ion storage mechanism utilized in lithium-ion batteries. Innovations in synthetic methods, post-treatments, and interface engineering clearly demonstrate the significance of developing high-performance carbonaceous anode materials for sodium-ion batteries. The objective of this dissertation is to present a systematic approach for fabricating efficient, high-performance, and sustainable carbonaceous anode materials for sodium-ion batteries. This will involve a comprehensive investigation of different chemical environments and post-modification techniques as well. This dissertation focuses on three main objectives. Firstly, it explores the significance of post-synthetic methods in designing interfaces. A conformal carbon nitride coating is deposited through chemical vapor deposition on a carbon electrode as an artificial solid-electrolyte interface layer, resulting in improved electrochemical performance. The interaction between the carbon nitride artificial interface and the carbon electrode enhances initial Coulombic efficiency, rate performance, and total capacity. Secondly, a novel process for preparing sulfur-rich carbon as a high-performing anode material for sodium-ion batteries is presented. The method involves using an oligo-3,4-ethylenedioxythiophene precursor for high sulfur content hard carbon anode to investigate the sulfur heteroatom effect on the electrochemical sodium storage mechanism. By optimizing the condensation temperature, a significant transformation in the materials’ nanostructure is achieved, leading to improved electrochemical performance. The use of in-operando small-angle X-ray scattering provides valuable insights into the interaction between micropores and sodium ions during the electrochemical processes. Lastly, the development of high-capacity hard carbon, derived from 5-hydroxymethyl furfural, is examined. This carbon material exhibits exceptional performance at both low and high current densities. Extensive electrochemical and physicochemical characterizations shed light on the sodium storage mechanism concerning the chemical environment, establishing the material’s stability and potential applications in sodium-ion batteries. N2 - Die Abhängigkeit von fossilen Brennstoffen hat zu einem abnormalen Anstieg von Treibhausgasen in der Atmosphäre geführt, was zur globalen Klimakrise beiträgt. Als Reaktion darauf hat eine rasche Umstellung auf erneuerbare Energiequellen begonnen, insbesondere Lithium-Ionen-Batterien, die eine entscheidende Rolle in der grünen Energiewende spielen. Bedenken hinsichtlich der Verfügbarkeit und geopolitischen Implikationen von Lithium haben jedoch die Erforschung alternativer wiederaufladbarer Batteriesysteme wie Natrium-Ionen-Batterien angeregt. Natrium ist in der Erdkruste und im Meerwasser deutlich häufiger und gleichmäßiger verteilt, was seine Extraktion im Vergleich zu Lithium einfacher und kostengünstiger macht. Aufgrund der geheimnisvollen Natur ihrer Komponenten sind Natrium-Ionen-Batterien derzeit noch nicht ausreichend fortgeschritten, um Lithium-Ionen-Batterien zu ersetzen. Insbesondere weist Natrium einen stärker metallischen Charakter und einen größeren Ionenradius auf, was zu einem anderen Ionen-Speichermechanismus führt, der in Lithium-Ionen-Batterien verwendet wird. Innovationen in synthetischen, post-synthetischen Methoden und Schnittstellentechnik zeigen deutlich die Bedeutung der Entwicklung hochleistungsfähiger kohlenstoffhaltiger Anodenmaterialien für Natrium-Ionen-Batterien auf. Das Ziel dieser Dissertation ist es, einen systematischen Ansatz zur Herstellung effizienter, leistungsstarker und nachhaltiger kohlenstoffhaltiger Anodenmaterialien für Natrium-Ionen-Batterien zu untersuchen. Diese Dissertation konzentriert sich auf drei Hauptziele. Erstens untersucht sie die Bedeutung von post-synthetischen Methoden bei der Gestaltung von Schnittstellen. Eine konforme Kohlenstoffnitrid-Beschichtung wird durch chemische Gasphasenabscheidung auf einer Kohlenstoffelektrode als künstliche Festelektrolytschnittstelle abgeschieden, was zu einer verbesserten elektrochemischen Leistung führt. Die Wechselwirkung zwischen der künstlichen Kohlenstoffnitrid-Schnittstelle und der Kohlenstoffelektrode trägt zu einer verbesserten anfänglichen kolumbischen Effizienz, Leistung bei hohen Raten und Gesamtkapazität bei. Zweitens wird ein neuartiger Prozess zur Herstellung von schwefelreichem Kohlenstoff als hochleistungsfähiges Anodenmaterial für Natrium-Ionen-Batterien vorgestellt. Die Methode verwendet einen Oligo-3,4-ethylendioxythiophen-Vorläufer für eine harte Kohlenstoffanode mit hohem Schwefelgehalt, um den Effekt des Schwefelheteroatoms auf den elektrochemischen Natriumspeichermechanismus zu untersuchen. Durch Optimierung der Kondensationstemperatur wird eine bedeutende Transformation in der Nanostruktur des Materials erreicht, was zu einer verbesserten elektrochemischen Leistung führt. Der Einsatz von in-operando-Röntgenkleinwinkelstreuung liefert wertvolle Erkenntnisse über die Wechselwirkung zwischen Mikroporen und Natriumionen während der elektrochemischen Prozesse. Letzendlich wird die Entwicklung einer hochkapazitiven harten Kohlenstoffanode, die aus 5-Hydroxymethylfurfural gewonnen wird, untersucht. Dieses Kohlenstoffmaterial zeigt eine außergewöhnliche Leistung sowohl bei niedrigen als auch bei hohen Stromdichten. KW - sodium-ion battery KW - sulfur KW - carbon KW - CN KW - anode KW - in-operando SAXS KW - Kohlenstoffnitrid (CN) KW - Anode KW - Kohlenstoff KW - in-operando SAXS KW - Natrium-Ionen-Batterie KW - Schwefel Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-622585 ER - TY - JOUR A1 - Yan, Runyu A1 - Oschatz, Martin A1 - Wu, Feixiang T1 - Towards stable lithium-sulfur battery cathodes by combining physical and chemical confinement of polysulfides in core-shell structured nitrogen-doped carbons JF - Carbon N2 - Despite intensive research on porous carbon materials as hosts for sulfur in lithium-sulfur battery cathodes, it remains a problem to restrain the soluble lithium polysulfide intermediates for a long-term cycling stability without the use of metallic or metal-containing species. Here, we report the synthesis of nitrogen-doped carbon materials with hierarchical pore architecture and a core-shell-type particle design including an ordered mesoporous carbon core and a polar microporous carbon shell. The initial discharge capacity with a sulfur loading up to 72 wt% reaches over 900 mA h g(sulf)(ur)(-1) at a rate of C/2. Cycling performance measured at C/2 indicates similar to 90% capacity retention over 250 cycles. In comparison to other carbon hosts, this architecture not only provides sufficient space for a high sulfur loading induced by the high-pore-volume particle core, but also enables a dual effect of physical and chemical confinement of the polysulfides to stabilize the cycle life by adsorbing the soluble intermediates in the polar microporous shell. This work elucidates a design principle for carbonaceous hosts that is capable to provide simultaneous physical-chemical confinement. This is necessary to overcome the shuttle effect towards stable lithium-sulfur battery cathodes, in the absence of additional membranes or inactive metal-based anchoring materials. KW - lithium-sulfur battery KW - sulfur KW - porous carbon KW - cathode KW - polysulfides Y1 - 2020 U6 - https://doi.org/10.1016/j.carbon.2020.01.046 SN - 0008-6223 SN - 1873-3891 VL - 161 SP - 162 EP - 168 PB - Elsevier Science CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Mendel, Ralf R. A1 - Hercher, Thomas W. A1 - Zupok, Arkadiusz A1 - Hasnat, Muhammad Abrar A1 - Leimkühler, Silke T1 - The requirement of inorganic Fe-S clusters for the biosynthesis of the organometallic molybdenum cofactor JF - Inorganics : open access journal N2 - Iron-sulfur (Fe-S) clusters are essential protein cofactors. In enzymes, they are present either in the rhombic [2Fe-2S] or the cubic [4Fe-4S] form, where they are involved in catalysis and electron transfer and in the biosynthesis of metal-containing prosthetic groups like the molybdenum cofactor (Moco). Here, we give an overview of the assembly of Fe-S clusters in bacteria and humans and present their connection to the Moco biosynthesis pathway. In all organisms, Fe-S cluster assembly starts with the abstraction of sulfur froml-cysteine and its transfer to a scaffold protein. After formation, Fe-S clusters are transferred to carrier proteins that insert them into recipient apo-proteins. In eukaryotes like humans and plants, Fe-S cluster assembly takes place both in mitochondria and in the cytosol. Both Moco biosynthesis and Fe-S cluster assembly are highly conserved among all kingdoms of life. Moco is a tricyclic pterin compound with molybdenum coordinated through its unique dithiolene group. Moco biosynthesis begins in the mitochondria in a Fe-S cluster dependent step involving radical/S-adenosylmethionine (SAM) chemistry. An intermediate is transferred to the cytosol where the dithiolene group is formed, to which molybdenum is finally added. Further connections between Fe-S cluster assembly and Moco biosynthesis are discussed in detail. KW - Moco biosynthesis KW - Fe-S cluster assembly KW - l-cysteine desulfurase KW - ISC KW - SUF KW - NIF KW - iron KW - molybdenum KW - sulfur Y1 - 2020 U6 - https://doi.org/10.3390/inorganics8070043 SN - 2304-6740 VL - 8 IS - 7 PB - MDPI CY - Basel ER - TY - JOUR A1 - Wessig, Pablo A1 - Freyse, Daniel A1 - Schuster, David A1 - Kelling, Alexandra T1 - Fluorescent dyes with large stokes shifts based on Benzo[1,2-d:4,5-d']bis([1,3]dithiole) (“S4-DBD Dyes”) JF - Europan journal of organic chemistry N2 - We report on a further development of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes by replacement of the four oxygen atoms of the heterocyclic core by sulfur atoms. This variation causes striking changes of the photophysical properties. Whereas absorption and emission significantly shifted to longer wavelength, the fluorescence lifetimes and quantum yields are diminished compared to DBD dyes. The latter effect is presumably caused by an enhanced intersystem crossing to the triplet state due to the sulfur atoms. The very large Stokes shifts of the S-4-DBD dyes ranging from 3000 cm(-1) to 7400 cm(-1) (67 nm to 191 nm) should be especially emphasized. By analogy with DBD dyes a broad variation of absorption and emission wavelength is possible by introducing different electron withdrawing substituents. Moreover, some derivatives for coupling with biomolecules were developed. KW - fluorescent dyes KW - sulfur KW - heterocycles KW - stokes shift KW - photophysics Y1 - 2020 U6 - https://doi.org/10.1002/ejoc.202000093 SN - 1434-193X SN - 1099-0690 VL - 2020 IS - 11 SP - 1732 EP - 1744 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Wessig, Pablo A1 - John, Leonard A1 - Sperlich, Eric A1 - Kelling, Alexandra T1 - Sulfur tuning of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes JF - European journal of organic chemistry N2 - The replacement of oxygen by sulfur atoms of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes is an efficient way to adjust the photophysical properties (sulfur tuning). While previously developed S-4-DBD dyes exhibit considerably red-shifted absorption and emission wavelength, the heavy atom effect of four sulfur atoms cause low fluorescence quantum yields and short fluorescence lifetimes. Herein, we demonstrate that the replacement of less than four sulfur atoms (S-1-DBD, 1,2-S-2-DBD, and 1,4-S-2-DBD dyes) permits a fine-tuning of the photophysical properties. In some cases, a similar influence on the wavelength without the detrimental effect on the quantum yields and lifetimes is observed. Furthermore, the synthetic accessibility of S-1- and S-2-DBD dyes is improved, compared with S-4-DBD dyes. For coupling with biomolecules a series of reactive derivatives of the new dyes were developed (azides, OSu esters, alkynes, maleimides). KW - fluorescent dyes KW - heterocycles KW - photophysics KW - stokes shift KW - sulfur Y1 - 2020 U6 - https://doi.org/10.1002/ejoc.202001418 SN - 1434-193X SN - 1099-0690 VL - 2021 IS - 3 SP - 499 EP - 511 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Lever, Fabiano A1 - Mayer, Dennis A1 - Metje, Jan A1 - Alisauskas, Skirmantas A1 - Calegari, Francesca A1 - Düsterer, Stefan A1 - Feifel, Raimund A1 - Niebuhr, Mario A1 - Manschwetus, Bastian A1 - Kuhlmann, Marion A1 - Mazza, Tommaso A1 - Robinson, Matthew Scott A1 - Squibb, Richard J. A1 - Trabattoni, Andrea A1 - Wallner, Måns A1 - Wolf, Thomas J. A. A1 - Gühr, Markus T1 - Core-level spectroscopy of 2-thiouracil at the sulfur L1 and L2,3 edges utilizing a SASE free-electron-laser JF - Molecules N2 - In this paper, we report X-ray absorption and core-level electron spectra of the nucleobase derivative 2-thiouracil at the sulfur L1- and L2,3-edges. We used soft X-rays from the free-electron laser FLASH2 for the excitation of isolated molecules and dispersed the outgoing electrons with a magnetic bottle spectrometer. We identified photoelectrons from the 2p core orbital, accompanied by an electron correlation satellite, as well as resonant and non-resonant Coster–Kronig and Auger–Meitner emission at the L1- and L2,3-edges, respectively. We used the electron yield to construct X-ray absorption spectra at the two edges. The experimental data obtained are put in the context of the literature currently available on sulfur core-level and 2-thiouracil spectroscopy. KW - X-ray KW - photoelectron KW - sulfur KW - thiouracil KW - nucleobases KW - Coster–Kronig KW - Auger–Meitner KW - NEXAFS KW - FLASH Y1 - 2021 SN - 1420-3049 VL - 26 IS - 21 PB - MDPI CY - Basel ER - TY - GEN A1 - Lever, Fabiano A1 - Mayer, Dennis A1 - Metje, Jan A1 - Alisauskas, Skirmantas A1 - Calegari, Francesca A1 - Düsterer, Stefan A1 - Feifel, Raimund A1 - Niebuhr, Mario A1 - Manschwetus, Bastian A1 - Kuhlmann, Marion A1 - Mazza, Tommaso A1 - Robinson, Matthew Scott A1 - Squibb, Richard J. A1 - Trabattoni, Andrea A1 - Wallner, Måns A1 - Wolf, Thomas J. A. A1 - Gühr, Markus T1 - Core-level spectroscopy of 2-thiouracil at the sulfur L1 and L2,3 edges utilizing a SASE free-electron-laser T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In this paper, we report X-ray absorption and core-level electron spectra of the nucleobase derivative 2-thiouracil at the sulfur L1- and L2,3-edges. We used soft X-rays from the free-electron laser FLASH2 for the excitation of isolated molecules and dispersed the outgoing electrons with a magnetic bottle spectrometer. We identified photoelectrons from the 2p core orbital, accompanied by an electron correlation satellite, as well as resonant and non-resonant Coster–Kronig and Auger–Meitner emission at the L1- and L2,3-edges, respectively. We used the electron yield to construct X-ray absorption spectra at the two edges. The experimental data obtained are put in the context of the literature currently available on sulfur core-level and 2-thiouracil spectroscopy. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1180 KW - X-ray KW - photoelectron KW - sulfur KW - thiouracil KW - nucleobases KW - Coster–Kronig KW - Auger–Meitner KW - NEXAFS KW - FLASH Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-524091 SN - 1866-8372 IS - 21 ER - TY - THES A1 - John, Leonard T1 - Neuartige DBD-Fluoreszenzfarbstoffe T1 - Novel DBD-fluorescent dyes BT - Synthese, Untersuchungen und Anwendungen BT - synthesis, investigations and applications N2 - Zusammenfassung zur Dissertation „Neuartige DBD-Fluoreszenzfarbstoffe: Synthese, Untersuchungen und Anwendungen“ von Leonard John In dieser Arbeit konnten auf Basis der etablierten [1,3]-Dioxolo[4,5-f][1,3]benzodioxol (DBD) Fluoreszenzfarbstoffe zwei neue Konzepte zur Darstellung unsymmetrisch funktionalisierter DBD-Fluorophore entwickelt werden. Die Variation der elektronenziehenden Reste führte zu einer Erweiterung des Farbspektrums an DBD-Fluorophoren, wobei alle weiteren spektroskopischen Parameter (Fluoreszenzlebenszeit, -quantenausbeute und STOKES-Verschiebung) unverändert hohe Werte aufweisen. Neben der Variation der elektronenziehenden Reste wurde das "pi"-System des DBD-Farbstoffs mit der Einführung von Stilben-, und Tolan-Derivaten vergrößert. Stilben-Derivate zeigten ähnlich gute spektroskopische Eigenschaften wie die bereits etablierten DBD-Farbstoffe. Fluorophore mit langwelliger Emission sind auf Grund der großen Gewebe-Eindringtiefe besonders interessant für biologische Anwendungen. Da der langwelligste Vertreter der O4-DBD-Farbstoffe in polaren Medien nur schwer löslich ist, wurde ein Weg zur Einführung löslichkeitsvermittelnder Gruppen gesucht. Hierbei fiel die Wahl auf eine Carbonsäure-Gruppe zur Steigerung der Hydrophilie. Eine von vier untersuchten Methoden erwies sich als zielführend, sodass das gewünschte Molekül isoliert werden konnte. Eine erhöhte Wasserlöslichkeit wurde allerdings nicht beobachtet. Zur Erforschung von Fettstoffwechselkrankheiten wie der ALZHEIMER-Krankheit werden fluoreszenzmarkierte Lipide benötigt. Um unterschiedliche Bereiche einer Membran zu untersuchen, war das Ziel, den Fluorophor an unterschiedlichen Stellen innerhalb der Fettsäure zu lokalisieren. Hierbei sollte die Gesamtkettenlänge des DBD-Lipids einer C18-Kette, analog der Stearinsäure, entsprechen. Durch die stufenweise Einführung der Reste gelang es, drei DBD-Lipide herzustellen, wobei sich der Fluorophor an unterschiedlichen Positionen innerhalb der Kette befindet. Die photophysikalischen Eigenschaften der Lipide weichen nur marginal von denen der reinen Fluorophore ab. Eine Einlagerung in giant unilamellar vesicles (GUVs) konnte für zwei Derivate beobachtet werden, wobei keine domänenspezifisch war. Ein weiteres Ziel dieser Arbeit war es, die vier Sauerstoffatome im DBD-Grundkörper stufenweise durch Schwefelatome zu ersetzen und die Ringgrößen des DBD-Fluorophors zu variieren. Für die Ringgröße zeigte der 1,2-S2-DBD mit jeweils zwei Fünfringen die besten spektroskopischen Eigenschaften. Durch die Synthese von zwei weiteren schwefelhaltigen DBD-Grundkörpern (S1- und 1,4-S2-DBD) konnten insgesamt drei neue Farbstoffklassen zugänglich gemacht werden. Für alle neuen Chromophore wurden elektronenziehende Reste (Aldehyd, Acyl, Ester, Carboxy) eingeführt und die jeweiligen Derivate spektroskopisch untersucht. Mit steigender Anzahl an Schwefel-Atomen im Grundkörper zeigt sich eine bathochrome Verschiebung der Emission, wobei die Werte für die Fluoreszenzlebenszeit- und -quantenausbeute abnehmen. Die optimalen spektroskopischen Eigenschaften aus langwelliger Emission, hoher Fluoreszenzlebenszeit und -quantenausbeute zeigt das 1,4-S2-Dialdehyd-Derivat. Für die S1- und 1,2-S2-Dialdehyd- Derivate wurden Konzepte entwickelt, um bioreaktive Reste (Alkin, HOSu, Maleimid) einzuführen und die Fluorophore in biologischen Systemen anwenden zu können. N2 - Abstract for the Dissertation „Neuartige DBD-Fluoreszenzfarbstoffe: Synthese, Untersuchungen und Anwendungen“ by Leonard John In this work, two new concepts for the preparation of asymmetrically functionalized DBD fluorophores were developed based on the established [1,3]dioxolo[4,5-f][1,3]benzodioxole (DBD) fluorescent dyes. Variation of the electron-withdrawing groups led to an expansion of the color spectrum of DBD fluorophores, with all other spectroscopic parameters (fluorescence lifetime, quantum yield, and STOKES- shift) showing unchanged high values. In addition to the variation of electron-withdrawing groups, the "pi"-system of the DBD dye was enlarged with the introduction of stilbene, and tolane derivatives. Stilbene derivatives showed similar good spectroscopic properties as the already established DBD dyes. Fluorophores with long wavelength emission are particularly interesting for biological applications due to their large tissue penetration depth. Since the longest wavelength representative of the O4-DBD dyes is poorly soluble in polar media, a way to introduce solubility-mediating groups was sought. Here, the choice fell on a carboxylic acid group to increase hydrophilicity. One of four methods investigated proved to be effective, so that the desired molecule could be isolated. However, increased water solubility was not observed. Fluorescently labeled lipids are needed to study lipid metabolism diseases such as ALZHEIMER disease. In order to study different areas of a membrane, the goal was to localize the fluorophore at different sites within the fatty acid. Here, the total chain length of the DBD lipid should correspond to a C18 chain, analogous to stearic acid. By introducing the residues stepwise, it was possible to prepare three DBD lipids with the fluorophore located at different positions within the chain. The photophysical properties of the lipids differ only marginally from those of the pure fluorophores. Incorporation into giant unilamellar vesicles (GUVs) was observed for two derivatives, although none was domain specific. Another goal of this work was to gradually replace the four oxygen atoms in the DBD parent with sulfur atoms and to vary the ring sizes of the DBD fluorophore. For the ring size, the 1,2-S2-DBD with two five-membered rings each showed the best spectroscopic properties. The synthesis of two additional sulfur-containing DBD precursors (S1- and 1,4-S2-DBD) made a total of three new dye classes accessible. Electron-withdrawing residues (aldehyde, acyl, ester, carboxy) were introduced for all new chromophores and the respective derivatives were investigated spectroscopically. As the number of sulfur atoms in the parent compound increases, a bathochromic shift in emission is seen, with decreasing values for fluorescence lifetime and quantum yield. The optimal spectroscopic properties of long wavelength emission, high fluorescence lifetime and quantum yield are exhibited by the 1,4-S2-dialdehyde derivative. For the S1- and 1,2-S2-dialdehyde derivatives, concepts were developed to introduce bioreactive residues (alkyne, HOSu, maleimide) and to apply the fluorophores in biological systems. KW - Organische Chemie KW - Fluoreszenzfarbstoffe KW - DBD-Farbstoffe KW - Schwefel KW - sulfur KW - DBD-dyes KW - fluorescent dyes KW - organic chemistry Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-510487 ER - TY - JOUR A1 - Wang, Qiong A1 - Mosconi, Edoardo A1 - Wolff, Christian Michael A1 - Li, Junming A1 - Neher, Dieter A1 - De Angelis, Filippo A1 - Suranna, Gian Paolo A1 - Grisorio, Roberto A1 - Abate, Antonio T1 - Rationalizing the molecular design of hole-selective contacts to improve charge extraction in Perovskite solar cells JF - dvanced energy materials N2 - Two new hole selective materials (HSMs) based on dangling methylsulfanyl groups connected to the C-9 position of the fluorene core are synthesized and applied in perovskite solar cells. Being structurally similar to a half of Spiro-OMeTAD molecule, these HSMs (referred as FS and DFS) share similar redox potentials but are endowed with slightly higher hole mobility, due to the planarity and large extension of their structure. Competitive power conversion efficiency (up to 18.6%) is achieved by using the new HSMs in suitable perovskite solar cells. Time-resolved photoluminescence decay measurements and electrochemical impedance spectroscopy show more efficient charge extraction at the HSM/perovskite interface with respect to Spiro-OMeTAD, which is reflected in higher photocurrents exhibited by DFS/FS-integrated perovskite solar cells. Density functional theory simulations reveal that the interactions of methylammonium with methylsulfanyl groups in DFS/FS strengthen their electrostatic attraction with the perovskite surface, providing an additional path for hole extraction compared to the sole presence of methoxy groups in Spiro-OMeTAD. Importantly, the low-cost synthesis of FS makes it significantly attractive for the future commercialization of perovskite solar cells. KW - hole extraction KW - hole selective materials KW - perovskite solar cells KW - sulfur KW - triple-cation perovskite Y1 - 2019 U6 - https://doi.org/10.1002/aenm.201900990 SN - 1614-6832 SN - 1614-6840 VL - 9 IS - 28 PB - Wiley-VCH CY - Weinheim ER -