Mirosława Kępińska

Flower-like BiOI nanoplates were successfully synthesized via a simple and eco-friendly chemical precipitation route and evaluated as flexocatalysts for the ultrasonic degradation of organic pollutants.

The self‐powered, adaptable, quick, and precise humidity sensors are required to measure humidity in the microenvironment. Here, a simple one‐step wet chemical method is presented to prepare stacked layered bismuth oxyiodide (BiOI) nanoplates. The remarkable response and self‐powered behavior of BiOI nanoplates‐based humidity sensors are demonstrated for the first time. The humidity sensing characteristics of BiOI are examined within the range of 30–80% relative humidity (RH) at an operating temperature of 323 K. The highest sensitivity level of 39 kΩ per %RH is determined for a relative humidity of 75.5%. A successful attempt is made to use this sensor as a human breathing process monitor. The sensor response times at room temperature in this test are 3.04(9) s at 0 V and 3.31(7) s at 20 V, whereas the recovery times are estimated to be 6.57(6) s at 0 V and 6.42(4) s at 20 V. Future advancements in sensing devices utilizing BiOI hold the potential to yield highly responsive, ultrafast sensors with simplified device geometries, and self‐powered.

This work describes a novel method for converting bismuth triiodide (BiI₃) microplates into bismuth oxyiodide (BiOI) nanoflakes under ultrasonic irradiation. To produce BiOI nanoflakes with a high yield and high purity, the conversion process was carefully adjusted. Rapid reaction kinetics and increased mass transfer are benefits of the ultrasonic-assisted approach that result in well-defined converted BiOI nanostructures with superior characteristics. The produced BiOI nanoflakes were examined utilizing a range of analytical methods, such as Transmission Electron Microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The progress in the ultrasonic conversion process with time was monitored through diffuse reflectance spectroscopy (DRS). The outcomes demonstrated the effective conversion of BiI₃ microplates into crystalline, homogeneous, high-surface-area BiOI nanoflakes. Additionally, the degradation of organic dyes (methylene blue) under ultraviolet (UV) light irradiation was used to assess the photocatalytic efficacy of the produced BiOI nanoflakes. Because of their distinct morphology and electrical structure, the BiOI nanoflakes remarkably demonstrated remarkable photocatalytic activity, outperforming traditional photocatalysts. The ability of BiOI nanoflakes to effectively separate and utilize visible light photons makes them a viable option for environmental remediation applications. This work not only shows the promise of BiOI nanoflakes for sustainable photocatalytic applications but also demonstrates a simple and scalable approach to their manufacturing. The knowledge gathered from this work opens up new avenues for investigating ultrasonic-assisted techniques for creating sophisticated nanomaterials with customized characteristics for a range of technological uses.

Photonic crystals are artificial structures with a spatial periodicity of dielectric permittivity on the wavelength scale. This feature results in a spectral region over which no light can propagate within such a material, known as the photonic band gap (PBG). It leads to a unique interaction between light and matter. A photonic crystal can redirect, concentrate, or even trap incident light. Different materials (dielectrics, semiconductors, metals, polymers, etc.) and 1D, 2D, and 3D architectures (layers, inverse opal, woodpile, etc.) of photonic crystals enable great flexibility in designing the optical response of the material. This opens an extensive range of applications, including photovoltaics. Photonic crystals can be used as anti-reflective and light-trapping surfaces, back reflectors, spectrum splitters, absorption enhancers, radiation coolers, or electron transport layers. This paper presents an overview of the developments and trends in designing photonic structures for different photovoltaic applications.

In the past twenty years, the basic investigation of innovative Non-Linear Optical (NLO) crystals has received significant attention, which has built the crucial heritage for the use of NLO materials. Fundamental research is essential given the scarcity of materials for NLO compounds, especially in the deep ultraviolet (DUV) and middle- and far-infrared (MFIR) regions. In the present work, we synthesized high-quality MFIR SbI₃·3S₈ NLO crystals having a length in the range of 1–5 mm through rapid facile liquid phase ultrasonic reaction followed by the assistance of instantaneous natural evaporation phenomenon of the solvent at room temperature. X-ray diffraction (XRD) results ratify the hexagonal R3m structure of SbI₃·3S₈ crystal, and energy-dispersive X-ray spectroscopy (EDX) demonstrates that the elemental composition of SbI₃·3S₈ crystal is similar to that of its theoretical composition. The direct and indirect forbidden energy gaps of SbI₃·3S₈ were measured from the optical transmittance spectra and they were shown to be 2.893 eV and 1.986 eV, respectively. The green sparkling signal has been observed from the crystal during the second harmonic generation (SHG) experiment. Therefore, as inorganic adducts are often explored as NLO crystals, this work on the MFIR SbI₃·3S₈ NLO crystal can bring about additional investigations on this hot topic in the near future.

Piezocatalysis is a novel method that can be applied for degradation of organic pollutants in wastewater. In this paper, ferroelectric nanowires of antimony sulfoiodide (SbSI) have been fabricated using a sonochemical method. Methyl orange (MO) was chosen as a typical pollutant, as it is widely used as a dye in industry. An aqueous solution of MO at a concentration of 30 mg/L containing SbSI nanowires (6 g/L) was subjected to ultrasonic vibration. High degradation efficiency of 99.5% was achieved after an extremely short period of ultrasonic irradiation (40 s). The large reaction rate constant of 0.126(8) s⁻¹ was determined for piezocatalytic MO decomposition. This rate constant is two orders of magnitude larger than values of reaction rate constants reported in the literature for the most efficient piezocatalysts. These promising experimental results have proved a great potential of SbSI nanowires for their application in environmental purification and renewable energy conversion.

The laser surface texturing of coated glass by picosecond laser with 355nm wavelength strongly absorbed by the glass is reported. The texturing was performed using various pulse energy and the distance of ablative single mark on the coated glass surface. In the performed experiment it was possible to control for the surface’s optical reflectance.