Michael Pereira Martins


Last Name

Pereira Martins

First Name

Michael

ORCID

0000-0002-8165-1221

Organisational unit

09794 - Güntner, Andreas / Güntner, Andreas

Filters

2023 - 20255
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Publications 1 - 5 of 5
  • Porous metal nitride film synthesis without template
    Item type: Working Paper
    Baut, Adrien; Pereira Martins, Michael; Güntner, Andreas (2024)
    arXiv
    Metal nitrides possess exceptional catalytic, electronic and physical properties making them widely used in (opto-)electronics and as hard coatings. When used as films in surface-active applications, however, their performance remains limited by poor mass transfer and reduced accessibility of reactive sites. This is associated to compact film architecture yielded by conventional deposition techniques (e.g., 16-26% for sputtered W$_2$N). Here, we demonstrate a template-free method for the design of highly porous (porosity > 84%) metal nitride films with high compositional versatility, as demonstrated for Cu3N, W2N, MoNx and TiN. These are obtained by exploiting the self-assembly of fractal-like metal oxide agglomerates during deposition from aerosols followed by their dry nitridation. In case of Cu$_3$N, monocristalline oxide nanoparticles were converted to polycrystalline nitrides during nitridation, as traced by X-ray diffraction and electron microscopy. Such films feature consistently lower resistances than their metal oxide counterparts, as well as high reactivity and mass transfer. This is exploited exemplarily for molecular sensing of NO$_2$ at only 75$^\circ$C temperature, leading to up to a five-fold higher response with faster response time over more compact spin-coated films for. As a result, our approach overcomes critical mass transfer performance limitations of metal nitride films that are also relevant for other applications like electrocatalysis and energy storage.
  • Template-Free Synthesis of Highly Porous Metal Nitride Architectures for Electronics and Molecular Sensing
    Item type: Journal Article
    Baut, Adrien; Pereira Martins, Michael; Güntner, Andreas (2025)
    Small Structures
    Metal nitrides (MN) possess exceptional catalytic, electronic, and physical properties making them widely used in (opto-)electronics and as hard coatings. When used as films in surface-active applications, however, their performance remains limited by poor mass transfer and reduced accessibility of reactive sites. This is associated to compact film architecture yielded by conventional deposition techniques (e.g., sputtering). Herein, a template-free method for the design of highly porous (≥84%) MN films with high compositional versatility, as shown for Cu3N, W2N, MoNx, and TiN, is demonstrated. These are obtained by conversion of fractal-like metal oxide (MOx) agglomerated films through dry nitridation. In case of Cu3N, monocrystalline oxide nanoparticles are converted to polycrystalline nitrides, as traced by X-ray diffraction and electron microscopy. Such films feature consistently lower resistances than their MOx counterparts, as well as high reactivity and mass transfer. This is exploited exemplarily for molecular sensing of NO2 at only 75 °C temperature, leading to up to a fivefold higher response with faster response time over more compact spin-coated films. As a result, this approach overcomes critical mass transfer performance limitations of MN films that are also relevant for other applications like electrocatalysis and energy storage.
  • Room temperature NO2 chemiresistive sensing with porous WS2 films
    Item type: Working Paper
    Hersberger, Simone; Pereira Martins, Michael; Fassbind, Selina; et al. (2025)
    ChemRxiv
    Nitrogen dioxide (NO2) is a hazardous air pollutant with a lowered annual mean exposure limit from 40 to 10 µg/m3 (~5 parts-per-billion by volume, ppb) by the World Health Organization in 2021. This motivates the exploration of low-power and cost-efficient sensors that can detect such low concentrations of NO2, exhibit high selectivity against interfering analytes and resilience to humidity fluctuations. Here, a selective, stable and humidity-robust sensor for NO2 sensing at room temperature is presented. Flame-aerosol deposition followed by dry sulfidation results in highly porous (98%) and nanostructured WS2 films. These films exhibit a fivefold increase in response and over an order-of-magnitude reduction in response time, compared to conventional spin-coated films. Remarkable sensing performance down to 1 ppb of NO2 (with a signal-to-noise ratio of 12.9) is achieved with high selectivity (>164) towards environmental interferents including NH3, NO, acetone, H2S, benzene, CO, ethanol, methanol, N2O and toluene. We also reveal high robustness (response change ± 18%) against varying relative humidity (0 – 90%) and response stability over more than 6 months (± 10%). This sensor outperforms previously reported NO2 sensors operating at room temperature, making it well-suited for integration into devices for environmental monitoring or wearables for personal exposure assessment.
  • Dynamics of soot surface growth and agglomeration by enclosed spray combustion of jet fuel
    Item type: Journal Article
    Trivanovic, Una; Pereira Martins, Michael; Benz, Simon; et al. (2023)
    Fuel
  • Selective, Stable and Humidity-Robust NO2 Sensing at Room Temperature with Porous WS2 Films
    Item type: Journal Article
    Hersberger, Simone; Pereira Martins, Michael; Fassbind, Seina; et al. (2025)
    ACS Sensors
    Nitrogen dioxide (NO2) is a hazardous air pollutant with a lowered annual mean exposure limit from 40 to 10 μg/m3 (∼5 parts-per-billion by volume, ppb) by the World Health Organization in 2021. This motivates the exploration of low-power and cost-efficient sensors that can detect such low concentrations of NO2, exhibit high selectivity against interfering analytes and resilience to humidity fluctuations. Here, a selective, stable and humidity-robust sensor for NO2 sensing at room temperature is presented. Flame-aerosol deposition followed by dry sulfidation results in highly porous (98%) and nanostructured WS2 films. These films exhibit a 5-fold increase in response and over an order-of-magnitude reduction in response time, compared to conventional spin-coated films. Remarkable sensing performance down to 1 ppb of NO2 (with a signal-to-noise ratio of 12.9) is achieved with high selectivity (>164) toward environmental interferents including NH3, NO, acetone, H2S, benzene, CO, ethanol, methanol, N2O and toluene. We also reveal high robustness (response change ± 18%) against varying relative humidity (0–90%) and response stability over more than 6 months (±10%). This sensor outperforms previously reported NO2 sensors operating at room temperature, making it well-suited for integration into devices for environmental monitoring or wearables for personal exposure assessment.
Publications 1 - 5 of 5