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Item type:Publication, Access status: with files , Enhancing interfacial charge transport in Gold Nanoparticle@Polyaniline hybrids via N-heterocyclic carbene linkersN-Heterocyclic carbenes (NHCs) have emerged as a unique class of ligands for gold nanoparticles (Au NPs), combining strong metal binding with intrinsic electronic conductivity. Yet over the past decade, studies on Au NP@NHC systems have primarily focused on their stability, while the conductivity of NHCs has remained largely unexplored due to synthesis challenges. Here, we present a synthetic strategy that addresses this gap by employing amino-functionalized NHC-Au complexes with in situ oxidative polymerization of polyaniline (PANI) to yield electronically coupled Au NP@NHC-PANI hybrids in aqueous media. This strategy enables both a controlled PANI shell growth and introduction of an electronically active NHC interlayer. Single-particle scattering spectroscopy reveals that NHCs improve the interfacial electronic coupling as evidenced by pronounced plasmonic linewidth broadening. Conductivity measurements further confirm that NHCs enhance charge transport: conductive atomic force microscopy (C-AFM) shows an increase in contact current from 14.6 to 99.4 pA under a 300-mV bias, while lateral four-probe conductance increases from 0.17 to 3.5 nS. These results provide the first direct experimental evidence of the conductive role of NHCs in hybrid NP-polymer systems, establishing a new interface-engineering strategy for the rational design of electronically delocalized nanostructures and their applications in nanoelectronics.Publicationtype: Journal Article57 13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Strategies for optimizing hydrophobic semiconducting polymers for OECTs: modifications and additives(2026); Organic electrochemical transistors (OECTs) are promising for bioelectronics and neuromorphic computing but face challenges with organic mixed ion-electron conductors (OMIECs), such as swelling and limited synthesis flexibility. This research explores the synthesis of organometallics ruthenium (Ru)-containing polymetallaynes and engineering established hydrophobic organic semiconducting polymers (OSCPs). Ru-polymetallaynes were modified with different ligands to introduce ligand planarity and redox matching, where dithienopyrrole (DTP) showed the best performance due to enhanced metal-metal (M-M) interactions as a result of redox-matching, exhibiting enhanced state-retention ability and making it suitable for non-volatile memory applications. To improve OSCPs’ OECT performance, two metal-containing additives were investigated: poly(vinylferrocene) (PVF+) improved P3HT doping efficiency and device response time via enhanced hydrophilicity in the PVF+/P3HT blends, while poly(ethylene glycol) functionalized gold nanoparticles (PEG-AuNPs)/P3HT composites showed increased charge mobility (µ) and volumetric capacitance (C*), significantly improving OMIEC metrics such as µC*, making the OSCPs comparable to state-of-the-art OMIECs. Overall, incorporating metal-containing additives into hydrophobic OSCPs enhances both electronic and ionic performance, expanding the potential applications of this class of materials in OECTs.Publicationtype: Doctoral Thesis46 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Boosting OECT performance with PEGylated gold nanoparticles in hydrophobic channelsOrganic electrochemical transistors (OECTs) require organic mixed ion-electron conductors (OMIECs) (i.e., hydrophilic materials supporting electron and ion transportation) as active materials. However, high-performance OMIECs grafted with hydrophilic side chains are difficult to synthesize and purify, and often suffer from swelling during operation. In contrast, the synthetic pathways toward a broad range of hydrophobic polymeric semiconductors used in classic organic-field-effect transistors are well established, and several are even commercially available. Yet, these hydrophobic materials do not intrinsically support ionic transport, limiting their application in OECTs. Here, poly(ethyleneglycol) (PEG)-coated gold nanoparticles (AuNP) are incorporated into conventional hydrophobic polymeric semiconductors like poly-3-hexylthiophene (P3HT), improving not only ionic but also electronic transport. The hydrophilic AuNPs modify P3HT crystallite orientation, shorten lamellar and π–π distances, and create pathways for ion penetration, as evidenced by GIWAXS and AFM studies. With 5 wt% AuNP loading, OECTs achieve µC* of 98 F cm−1 V−1 s−1, comparable to hydrophilic materials. The strategy also works for other polymer systems, offering a facile method to utilize hydrophobic materials in OECTs and boost their performance.Publicationtype: Journal Article38 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Carboxylic Groups via Postpolymerization Modification of Polythiophene and their Influence on the Performance of a Polymeric MALDI Matrix(2023-01-01); ; ; ; Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) requires a matrix, and traditionally small organic matrices (SOMs) carrying acidic or basic functional groups are used. However, the analyte ionization via secondary processes in the gas-phase seems to be more important than primary processes. For conjugated polymeric matrices, an even more complicated picture emerges due to their apolar and aprotic nature, high molecular weight, and low tendency to desorb. Poly(3-dodecylthiophene-2,5-diyl) (P3DDT), a good matrix for low-molecular weight (LMW) analytes, does not give matrix-related peaks in the LMW area. Here, carboxylic acid (-COOH) side-chains are introduced via postpolymerization modification. The polymers are characterized by NMR, FT-IR, CV, MALDI MS, and, when possible, GPC. The electron withdrawing side-chains serve three functions; i) raising the ionization potential (IP), ii) improving the absorption maximum, and iii) acting as a source of protons. When measuring basic amines, this results in the occurrence of additional [Analyte + H+]+ signals compared to polymers without acidic groups, where only radical cations [Analyte]+• are detected. Similarly, estradiol and testosterone, compounds with high IPs, are not detected by polythiophenes without acidic groups, while P3DDT-COOH enables detection as protonated species.Publicationtype: Journal Article28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Synthesis of Novel Ruthenium-Polymetallaynes and Their Application in Multistate Electrochromic Memory(2022-12); ; ; ; Multilevel (or multistate) electrochromic devices have the potential to achieve highly compact memory capacity while instantaneously transferring data between memory and processing units. In this article, three novel solution-processable ruthenium-polymetallaynes (i.e., P1, P2, and P3), in which the redox-addressable Ru center is covalently embedded into a conjugated organic polymer, are discussed. In pursuit of higher functionality (e.g., stable multistate behavior, low operating voltage), the organic ligand bridging the metal centers is systematically varied. The previously reported P1 has a bithiophene (BT) bridging ligand with a high degree of rotational freedom. By replacing BT with cyclopenta-dithiophene in P2 and dithieno-pyrrole (DTP) in P3, both of which are more planar than BT, the degree of freedom is decreased. By using DTP, redox-matching is achieved between the metal center and organic ligand, leading to extra stability of the mixed-valence (MV) state in P3. In-depth experimental (i.e., in situ electron paramagnetic resonance and UV–vis–NIR spectroelectrochemistry) and theoretical studies (i.e., DFT calculations) are carried out on the polymer thin-films, showing enhanced metal–metal (M–M) interaction in P2 and P3 and stable Robin–Day class III MV compound in P3. These polymers are also first time fabricated into solid-state electrochromic devices and the stability of each oxidation state is characterized by tracing the change of transmittance over time, showing satisfactory cyclic stability and retention behavior (≈90% retention after 30 min).Publicationtype: Journal Article21 - 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 , Synthesis and charge transfer characteristics of a ruthenium-Acetylide complex(2020-11-27); ; ; ; A novel ruthenium-Acetylide complex was synthesised and characterised in solid state and solution. Thin films of the complex were evaporated on silver and gold foils in ultra high vacuum in order to probe the electronic properties with photoemission spectroscopy. The charge transfer characteristics of the complex with the strong acceptor F6TCNNQ were investigated by UV-vis absorption in solution as well as at an interface with photoemission spectroscopy. A new excitation in the former optical gap of the pristine materials was probed in solution. Moreover, it was possible to identify the oxidised complex as well as the reduced acceptor by X-ray photoemission spectroscopy. In particular, our data reveal that oxidation of the complex mainly occurs at the Ru centre. The charge transfer can be characterised as localised and mainly ionic although signs of a reaction of the acceptors aminogroups with the ruthenium-Acetylide complex were found. This journal isPublicationtype: Journal Article19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Synthesis and characterization of a semiconducting and solution-processable ruthenium-based polymetallayne(2020-01-14); ; ; ; Polymetallaynes are a special class of Wolf type-III polymers with high potential in organic electronics, especially in applications such as OFET, OLED and OPV. However, almost all reported polymetallaynes contain group 10 metals, while functional polymetallaynes with earlier transition metals have rarely been reported. Here, different synthetic routes to a group 8 polymetallayne P[Ru(dppe)2-DDBT], containing Ru(ii) centers bridged in the trans-position by the organic linker 3,3′-didodecyl-5,5′-diethynyl-2,2′-bithiophene (DDBT), are explored. The polymer is obtained by copper-free dehydrohalogenation, characterized using NMR, IR and UV-vis spectroscopy, MALDI-TOF-MS, GPC and CV. In solution, CV studies show two separated metal-centered redox processes, indicating that the charge between metal centers is delocalized via the bridging ligand and a mixed-valence species exists (Kc = 102). In thin-films, P[Ru(dppe)2-DDBT] exhibits a single oxidation wave with a higher peak current intensity, consistent with a two-electron process and localized charge. Despite a degree of polymerization ∼32 based on NMR and GPC studies, P[Ru(dppe)2-DDBT] is fully solution processable, and thin-films were obtained via spin-coating using different solvents. AFM investigations of the films showed very low surface roughness, and first OFET devices with a top-gate bottom-contact (TGBC) architecture were fabricated to characterize the electronic properties, confirming the semiconducting behaviour of the polymetallayne.Publicationtype: Journal Article21