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Start date: 2020 × End date: 2024 × Start date: 2020 × DDC: 620 × Subject: photocatalysis ×

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Now showing 1 - 3 of 3
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    Nanoimprint Lithography Facilitated Plasmonic-Photonic Coupling for Enhanced Photoconductivity and Photocatalysis
    (Weinheim : Wiley-VCH, 2021) Gupta, Vaibhav; Sarkar, Swagato; Aftenieva, Olha; Tsuda, Takuya; Kumar, Labeesh; Schletz, Daniel; Schultz, Johannes; Kiriy, Anton; Fery, Andreas; Vogel, Nicolas; König, Tobias A.F.
    Imprint lithography has emerged as a reliable, reproducible, and rapid method for patterning colloidal nanostructures. As a promising alternative to top-down lithographic approaches, the fabrication of nanodevices has thus become effective and straightforward. In this study, a fusion of interference lithography (IL) and nanosphere imprint lithography on various target substrates ranging from carbon film on transmission electron microscope grid to inorganic and dopable polymer semiconductor is reported. 1D plasmonic photonic crystals are printed with 75% yield on the centimeter scale using colloidal ink and an IL-produced polydimethylsiloxane stamp. Atomically smooth facet, single-crystalline, and monodisperse colloidal building blocks of gold (Au) nanoparticles are used to print 1D plasmonic grating on top of a titanium dioxide (TiO2) slab waveguide, producing waveguide-plasmon polariton modes with superior 10 nm spectral line-width. Plasmon-induced hot electrons are confirmed via two-terminal current measurements with increased photoresponsivity under guiding conditions. The fabricated hybrid structure with Au/TiO2 heterojunction enhances photocatalytic processes like degradation of methyl orange (MO) dye molecules using the generated hot electrons. This simple colloidal printing technique demonstrated on silicon, glass, Au film, and naphthalenediimide polymer thus marks an important milestone for large-scale implementation in optoelectronic devices. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH
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    Phase-enabled metal-organic framework homojunction for highly selective CO2 photoreduction
    (London : Nature Publishing Group, 2021) Liu, Yannan; Chen, Chuanshuang; Valdez, Jesus; Meira, Debora Motta; He, Wanting; Wang, Yong; Harnagea, Catalin; Lu, Qiongquiong; Guner, Tugrul; Wang, Hao; Liu, Cheng-Hao; Zhang, Qingzhe; Huang, Shengyun; Yurtsever, Aycan; Chaker, Mohamed; Ma, Dongling
    Conversion of clean solar energy to chemical fuels is one of the promising and up-and-coming applications of metal–organic frameworks. However, fast recombination of photogenerated charge carriers in these frameworks remains the most significant limitation for their photocatalytic application. Although the construction of homojunctions is a promising solution, it remains very challenging to synthesize them. Herein, we report a well-defined hierarchical homojunction based on metal–organic frameworks via a facile one-pot synthesis route directed by hollow transition metal nanoparticles. The homojunction is enabled by two concentric stacked nanoplates with slightly different crystal phases. The enhanced charge separation in the homojunction was visualized by in-situ surface photovoltage microscopy. Moreover, the as-prepared nanostacks displayed a visible-light-driven carbon dioxide reduction with very high carbon monooxide selectivity, and excellent stability. Our work provides a powerful platform to synthesize capable metal–organic framework complexes and sheds light on the hierarchical structure-function relationships of metal–organic frameworks.
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    Advanced Hybrid GaN/ZnO Nanoarchitectured Microtubes for Fluorescent Micromotors Driven by UV Light
    (Weinheim : Wiley-VCH, 2020) Wolff, Niklas; Ciobanu, Vladimir; Enachi, Mihail; Kamp, Marius; Braniste, Tudor; Duppel, Viola; Shree, Sindu; Raevschi, Simion; Medina-Sánchez, Mariana; Adelung, Rainer; Schmidt, Oliver G.; Kienle, Lorenz; Tiginyanu, Ion
    The development of functional microstructures with designed hierarchical and complex morphologies and large free active surfaces offers new potential for improvement of the pristine microstructures properties by the synergistic combination of microscopic as well as nanoscopic effects. In this contribution, dedicated methods of transmission electron microscopy (TEM) including tomography are used to characterize the complex hierarchically structured hybrid GaN/ZnO:Au microtubes containing a dense nanowire network on their interior. The presence of an epitaxially stabilized and chemically extremely stable ultrathin layer of ZnO on the inner wall of the produced GaN microtubes is evidenced. Gold nanoparticles initially trigger the catalytic growth of solid solution phase (Ga1– xZnx)(N1– xOx) nanowires into the interior space of the microtube, which are found to be terminated by AuGa-alloy nanodots coated in a shell of amorphous GaOx species after the hydride vapor phase epitaxy process. The structural characterization suggests that this hierarchical design of GaN/ZnO microtubes could offer the potential to exhibit improved photocatalytic properties, which are initially demonstrated under UV light irradiation. As a proof of concept, the produced microtubes are used as photocatalytic micromotors in the presence of hydrogen peroxide solution with luminescent properties, which are appealing for future environmental applications and active matter fundamental studies. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim