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5. Characterization of sustainable biocompatible materials based on chitosan : cellulose composites containing sporopollenin exine capsulesDorota Korte, Mohanachandran Nair Sindhu Swapna, Hanna Budasheva, Patricia Cazón, Manisha Chhikara, Tina Škorjanc, Carmen Tripon, Alexandra Farcas, Egon Pavlica, Chieu D. Tran, Mladen Franko, 2024, izvirni znanstveni članek Ključne besede: material characterization, biocompatible materials, chitosan, sporopollenin exine capsules, beam deflection spectrometry
Objavljeno v RUNG: 29.10.2024; Ogledov: 1605; Prenosov: 0
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6. Multi-layer palladium diselenide as a contact material for two-dimensional tungsten diselenide field-effect transistorsGennadiy Murastov, Muhammad Awais Aslam, Simon Leitner, Vadym Tkachuk, Iva Plutnarová, Egon Pavlica, Raul D. Rodriguez, Zdeněk Sofer, Aleksandar Matković, 2024, izvirni znanstveni članek Opis: Tungsten diselenide (WSe2) has emerged as a promising ambipolar semiconductor material for field-effect transistors (FETs) due to its unique electronic properties, including a sizeable band gap, high carrier mobility, and remarkable on–off ratio. However, engineering the contacts to WSe2 remains an issue, and high contact barriers prevent the utilization of the full performance in electronic applications. Furthermore, it could be possible to tune the contacts to WSe2 for effective electron or hole injection and consequently pin the threshold voltage to either conduction or valence band. This would be the way to achieve complementary metal–oxide–semiconductor devices without doping of the channel material.This study investigates the behaviour of two-dimensional WSe2 field-effect transistors with multi-layer palladium diselenide (PdSe2) as a contact material. We demonstrate that PdSe2 contacts favour hole injection while preserving the ambipolar nature of the channel material. This consequently yields high-performance p-type WSe2 devices with PdSe2 van der Waals contacts. Further, we explore the tunability of the contact interface by selective laser alteration of the WSe2 under the contacts, enabling pinning of the threshold voltage to the valence band of WSe2, yielding pure p-type operation of the devices.
Ključne besede: field-effect transistor, tungsten diselenide, van der Waals, two-dimensional materials
Objavljeno v RUNG: 29.05.2024; Ogledov: 2702; Prenosov: 13
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7. Air-water interface-assisted synthesis and charge transport characterization of quasi-2d polyacetylene films with enhanced electron mobility via ring-opening polymerization of pyrroleKejun Liu, Nadiia Pastukhova, Egon Pavlica, Gvido Bratina, Xinliang Feng, 2024, drugi sestavni deli Opis: Water surfaces catalyze some organic reactions more effectively, making them unique for 2D organic material synthesis. This report introduces a new synthesis method via surfactant-monolayer-assisted interfacial synthesis on water surfaces for ring-opening polymerization of pyrrole, producing distinct polypyrrole derivatives with polyacetylene backbones and ionic substitutions. The synthesis result in quasi 2D polyacetylene (q2DPA) film with enhanced charge transport behavior. We employed time-of-flight photoconductivity (TOFP) measurements using pulsed laser light of tunable wavelength for photoexcitation of the charge carriers within the q2DPA film. The charge transport was measured in the lateral direction as a function of external bias voltage ranging from 0 V to 200 V. We observed high electron mobility ({\mu}) of q2DPA reaching values of 375 cm2 V-1 s-1 at bias voltage Vb = -20V and photon energy of 3.8 eV.
Ključne besede: air-water interface-assisted synthesis, time-of-flight photoconductivity, 2D polymers, quasi 2D polyacetylene, q2DPA
Objavljeno v RUNG: 09.04.2024; Ogledov: 2877; Prenosov: 7
Celotno besedilo (3,89 MB)
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8. High charge carrier mobility in thin films of quasi-two-dimensional polyacetylenes with sulphuric inter-chain linkersNadiia Pastukhova, Gvido Bratina, Egon Pavlica, 2023, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Quasi-two-dimensional conjugated polymers (q2DCP) have been described and recognised as crystalline, one- or two-layer polymer nanosheets prepared by arranging linear conjugated polymer chains in a 2D plane via non-covalent interchain interactions.[1,2] The extension of polymer dimensionality to two dimensions improves the alignment of individual polymer layers and overcomes the limitations associated with charge carrier hopping between polymer chains in one-dimensional and crosslinked polymers [3] Compared to other two-dimensional materials such as graphene or transition metal dichalcogenides, q2DCPs offer a high degree of flexibility in chemical design and are compatible with liquid-based processing methods. Various q2DCPs have been synthesized by surface active monolayer-assisted interfacial synthesis (SMAIS) [5]
The photoreaction of these materials is of particular interest due to their tunable properties such as band gap and associated wavelength-dependent photoexcitation, which enables a wide range of applications in optoelectronic devices. Using time-of-flight photoconductivity measurements (TOF-PC) [4], we investigate the charge transport properties of 2D polyacetylene prepared by the SMAIS method. A typical TOFP measurement of q2D polyacetylene is shown in Figure 1, using a focused nanosecond pulse laser at 325 nm and an electrode spacing of 250 µm. From the polarity of the bias voltage and the duration of the photocurrent, we can determine the polarity, velocity, and mobility of the photo-excited carriers as a function of the applied bias voltage and excitation wavelength. and observed electron mobility of 250 cm2/Vs, which is in the range of the most advanced organic single-crystal small-molecule semiconductors and almost an order of magnitude higher than linear polymeric semiconductors. We investigated the optical absorption and transmission on a lateral scale using scanning near-field optical microscopy (SNOM).
Ključne besede: 2D polymers, organic semiconductors, q2DPA, SNOM, time-of-flight photoconductivity
Objavljeno v RUNG: 25.03.2024; Ogledov: 3253; Prenosov: 4
 Povezava na datoteko
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