Mirosława Kępińska

Sonochemical preparation of SbSeI gel

A novel sonochemical method for direct preparation of nanocrystalline antimony selenoiodide (SbSeI) has been established. The SbSeI gel was synthesized using elemental Sb, Se, and I in the presence of ethanol under ultrasonic irradiation (35 kHz, 2W/cm(2)) at 50 degrees C for 2h. The product was characterized by using techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and optical diffuse reflection spectroscopy (DRS). The SEM and HRTEM investigations exhibit that the as-prepared samples are made up of large quantity nanowires with lateral dimensions of about 20-50 nm and lengths reaching up to several micrometers and single crystalline in nature.

Optical and photoelectrical properties of SbSI

The optical transmittance and reflectance of SbSI single crystals had been measured for photon energies from 1.5 to 2.6 eV in temperature range from 77 K to 343 K. The experimental data had been evaluated to determine anisotropic, spectral and temperature dependences of real part of refractive index and absorption coefficient of SbSI. The temperature dependence of the energy gap had been evaluated from the spectral characteristics of absorption of light with electric field parallel and perpendicular to the c axis of the SbSI. The phase transition had been determined from the temperature dependences of optical parameters as well as from the temperature dependence of the energy gap. The photoconductivity of the investigated crystals had been measured as a function of photon energy, illumination intensity and temperature.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

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.

Surface and bulk values of real part of refractive index of GaSe

Optical transmittance and reflectance of crystalline gallium selenide (GaSe) pallets of different thicknesses had been determined for various photon energies (from 1.1 to 2.8 eV) as well as for different polarisations and angles of incidence upon a sample. Fitting of these results with appropriate formulae allowed us to determine values of real parts of refractive indices at the surface as well as in the bulk of the investigated material. Also the values of absorption coefficients had been determined. Values of these parameters for light with the electric vector parallel and perpendicular to the c-axis of the GaSe had been evaluated. The absorption mechanism had been recognised and the values of direct and indirect energy gaps as well as exciton energies had been found by fitting the spectral dependencies of optical parameters.

Using of sonochemically prepared SbSI for electrospun nanofibers

A novel polymeric, polyacrylonitrile (PAN) nanofibers containing ferroelectric and semiconducting antimony sulfoiodide (SbSI) have been made by electrospinning. SbSI nanowires, used as the filler, have been prepared sonochemically from antimony sulphide (Sb2S3) and antimony tri-iodide (SbI3) for the first time. Nanocrystalline SbSI has been fabricated in ethanol under ultrasonic irradiation (20kHz, 565W/cm2) at 323K within 2h. The products have been characterized by using techniques such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction and optical diffuse reflection as well as transmission spectroscopy. The good quality of the nanocrystals and their dispersion in the nanofibers volume is important because this material is attractive for nanogenerators due to its ferroelectric and piezoelectric properties. The amplitude of the voltage pulse, generated under shock pressure of 3.0MPa, has reached 180V in the prototype PAN/SbSI piezoelectric nanogenerator. The peak output voltage of about 0.2V was measured in bending/releasing conditions with the deformation frequency of 1Hz.

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.

Using of sonochemically prepared components for vapor phase growing of SbI3·3S8

The using of sonochemically prepared components for growth of SbI(3).3S(8) single crystals from the vapor phase is presented for the first time. The good optical quality of the obtained crystals is important because this material is valuable for optoelectronics due to its non-linear optical properties. The products were characterized by using techniques such as X-ray crystallography, powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction, optical diffuse reflection spectroscopy and optical transmittance spectroscopy. The direct and indirect forbidden energy gaps of SbI(3).3S(8) illuminated with plane polarized light with electric field parallel and perpendicular to the c-axis of the crystal have been determined. The second harmonic generation of light in the grown crystals was observed.

Temperature dependence of optical energy gap of GaSe

Summary form only given. Thin films and wafers of cleaved crystalline GaSe were investigated using optical reflectance (R) and transmittance (T) for wavelengths from 200 nm to 1050 nm. The investigations were performed at different temperatures from 77 K to 333 K using a cryogenic microminiature refrigeration system based on the Joule-Thomson effect. The derived spectra of the real part of the refractive index and the absorption coefficient are presented.

Temperature dependence of optical parameters of GaS

Summary form only given. GaS is a wide gap layered semiconductor. It has potentially many applications in optoelectronics. The presented work reports the temperature dependencies (77 K<T<335 K) and spectral dependencies of essential optical parameters: the real part of the refractive index and the absorption coefficient for light (1.18 eV<h/spl nu/<6.2 eV) with electric vector perpendicular and parallel to the c axis of the crystal. The temperature dependence of the optical energy gap and anisotropy coefficient of GaS are determined using these data.