Krystian Mistewicz

Ultrasonic processing of SbSI nanowires for their application to gas sensors

Ultrasonic processing has been applied to create durable electrical contacts between antimony sulfoiodide (SbSI) nanowires and Au microelectrodes on glass substrate. After DC electric field alignment of SbSI nanowires between the microelectrodes, the sample was irradiated with ultrasound using chromium copper alloy sonotrode ended with silicon carbide (SiC) single crystal. The SEM and AFM investigations have showed that the ends of SbSI nanowires have been well compacted and bonded with microelectrodes. Ultrasonic processing has caused 420% increase of DC electric conductance of the junctions between Au microelectrodes and SbSI nanowires. The fabricated structures of SbSI nanowires bonded to Au microelectrodes are useful e.g. as nitrous oxide (N2O) gas sensors. These low power devices can operate at room temperature and do not require heating system for recovery.

Comparison of the Investigations of Photonic Crystals Using SEM and Optical Technics

All over the world the investigations of nanophotonic structures called photonic crystals (PCs) are performed. These crystals have potential applications in optoelectronics, e.g. optical filters, antireflective surface coatings, lossless frequency selective mirrors. In Institute of Physics at Silesian Technical University the opal photonic crystals consisting of monodisperse spherical particles, that have diameters of several hundred nanometers, are produced using colloidal self-assembly technics. The main aim of this work is the comparison between pieces of information on morphology of photonic crystals that can be obtained from electron microscopy and from the angular characteristics of optical transmittance and reflectance. The morphology of the samples is characterized by scanning electron microscopy (SEM). Nanosphere diameters are established from statistical analysis of SEM images. The optical properties, which are determined by the photonic band structure, are studied by means of light transmission and reflection measurements. There is a relationship between the wavelength position of transmittance minimum or reflectance maximum and the diameter of the nanospheres. The size of nanospheres obtained from optical measurement results were compared with data obtained from SEM images.

Sonochemical growth of nanomaterials in carbon nanotube

HighlightsParameters of sonochemical encapsulation of SbSI and SbSeI in CNTs.SbSI@CNTs and SbSeI@CNTs bonded ultrasonically with microelectrodes.200% increase of conductance due to ultrasonic bonding of filled CNTs to Au.SbSI@CNTs and SbSeI@CNTs gas sensors do not require heating system for recovery.SbSI@CNTs structures applied to detect carbon dioxide. ABSTRACT Recent achievements in investigations of carbon nanotubes (CNTs) filled with ternary chalcohalides (antimony sulfoiodide (SbSI) and antimony selenoiodide (SbSeI)) are presented. Parameters of sonochemical encapsulation of nanocrystalline semiconducting ferroelectric SbSI‐type materials in CNTs are reported. This low temperature technology is convenient, fast, efficient and environmentally friendly route for producing novel type of hybrid materials useful for nanodevices. Structure as well as optical and electrical properties of SbSI@CNTs and SbSeI@CNTs are described. Advantages of ultrasonic joining of such filled CNTs with metal microelectrodes are emphasized. The possible applications of these nanomaterials as gas sensors are shown.

Antimony Sulfoiodide as Novel Material for Photonic Crystals

Semiconducting ferroelectrics promise construction of crystals with tuned photonic band gap. Such structures were synthesized by self-assembling SiO2 spheres, followed by melt infiltration with antimony sulfoiodide and the removal of SiO2 spheres by chemical etching.

Ferroelectric SbSI nanowires for ammonia detection at a low temperature

For the first-time, an ammonia (NH3) gas sensor has been fabricated using antimony sulfoiodide (SbSI). A few aligned SbSI nanowires have been bonded to Au microelectrodes on a glass substrate. The fabricated sensor has been tested for various concentrations of NH3 in N2 at operating temperatures below (T = 280 K) and above (T = 304 K) Curie point of SbSI. A significantly higher response and sensitivity of the sensor is observed, when the operating temperature is lower than Curie temperature. However, comparable values of the low detection limits (6.0 ± 2.4) ppm and (6.3 ± 3.9) ppm have been determined at operating temperatures of 280 K and 304 K, respectively. The current response, as well as the sensitivity versus ammonia concentration, follow the power laws known for conductometric gas sensors. SbSI nanosensor exhibits good stability, short term response reversibility, and does not require a heating system for recovery. This device also demonstrates a high selectivity to NH3 against other interfering gases. The ammonia sensing mechanism has been explained by considering the formation of NH4+ ions on the nanowire surface and the occurrence of proton transfer according to Grotthusss chain reaction.

Prevention of food spoilage using nanoscale sensors

Food products can be easily spoiled, even in the early stage of manufacture, as well as, when they are stored or transported improperly. The monitoring of humidity and excess gases in production, packaging, and storage processes has crucial significance for the quality and freshness of food. Nowadays, the nanoscale sensors show a great application potential in the food industry. In this chapter, many applications of them are reviewed, including detection of moisture, oxygen, carbon dioxide, amines, and microorganisms. Special attention is given to discuss the recently fabricated SbSI conductive and photoconductive humidity nanosensors. These small, highly sensitive, and low-power devices can address the requirements of food industry.