Filters

2020 - 20212

More filters

20212
Reset filters

Settings

Author: Kiriy, Nataliya × Author: Voit, Brigitte × Publisher: Weinheim : Wiley-VCH × WGL Institute: IPF ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    AB- Versus AA+BB-Suzuki Polycondensation: A Palladium/Tris(tert-butyl)phosphine Catalyst Can Outperform Conventional Catalysts
    (Weinheim : Wiley-VCH, 2020) Zhang, Kenan; Tkachov, Roman; Ditte, Kristina; Kiriy, Nataliya; Kiriy, Anton; Voit, Brigitte
    A Pd/Pt-Bu3 catalyst having bulky, electron-rich ligands significantly outperforms conventional “step-growth catalysts” Pd(PPh3)4 and Pd(Po-Tol3)3 in the Suzuki polycondensation of the AB-type arylene-based monomers, such as some of the substituted fluorenes, carbazoles, and phenylenes. In the AA+BB polycondensation, Pd/Pt-Bu3 also performs better under homogeneous reaction conditions, in combination with the organic base Et4NOH. The superior performance of Pd/Pt-Bu3 is discussed in terms of its higher reactivity in the oxidative addition step and inherent advantages of the intramolecular catalyst transfer, which is a key step joining catalytic cycles of the AB-polycondensation. These findings are applied to the synthesis of a carbazole-based copolymer designed for the use as a hole conductor in solution-processed organic light-emitting diodes. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
  • Thumbnail Image
    Item
    Self-Replication of Deeply Buried Doped Silicon Structures, which Remotely Control the Etching Process: A New Method for Forming a Silicon Pattern from the Bottom Up
    (Weinheim : Wiley-VCH, 2021) Schutzeichel, Christopher; Kiriy, Nataliya; Kiriy, Anton; Voit, Brigitte
    A typical microstructuring process utilizes photolithographic masks to create arbitrary patterns on silicon substrates in a top-down approach. Herein, a new, bottom-up microstructuring method is reported, which enables the patterning of n-doped silicon substrates to be performed without the need for application of etch-masks or stencils during the etching process. Instead, the structuring process developed herein involves a simple alkaline etching performed under illumination and is remotely controlled by the p-doped micro-sized implants, buried beneath a homogeneous n-doped layer at depths of 0.25 to 1 µm. The microstructuring is realized because the buried implants act upon illumination as micro-sized photovoltaic cells, which generate a flux of electrons and increase the negative surface charge in areas above the implants. The locally increased surface charge causes a local protection of the native silicon oxide layer from alkaline etching, which ultimately leads to the microstructuring of the substrate. In this way, substrates having at their top a thick layer of homogeneously n-doped silicon can be structured, reducing the need for costly, time-consuming photolithography steps. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH