M.M. Szindler

Silicon solar cells with Al2O3 antireflection coating

The paper presents the possibility of using Al2O3 antireflection coatings deposited by atomic layer deposition ALD. The ALD method is based on alternate pulsing of the precursor gases and vapors onto the substrate surface and then chemisorption or surface reaction of the precursors. The reactor is purged with an inert gas between the precursor pulses. The Al2O3 thin film in structure of the finished solar cells can play the role of both antireflection and passivation layer which will simplify the process. For this research 50×50 mm monocrystalline silicon solar cells with one bus bar have been used. The metallic contacts were prepared by screen printing method and Al2O3 antireflection coating by ALD method. Results and their analysis allow to conclude that the Al2O3 antireflection coating deposited by ALD has a significant impact on the optoelectronic properties of the silicon solar cell. For about 80 nm of Al2O3 the best results were obtained in the wavelength range of 400 to 800 nm reducing the reflection to less than 1%. The difference in the solar cells efficiency between with and without antireflection coating was 5.28%. The LBIC scan measurements may indicate a positive influence of the thin film Al2O3 on the bulk passivation of the silicon.

ZnO nanocrystalline powder preparedby sol-gel method for photoanode of dyesensitized solar cells application

Purpose: The article presents the results of research on ZnO nanopowder prepared using sol-gel method that is the easy process enabling us to control shape and size of particles The purpose of this article is to synthesized ZnO nanostructures by sol-gel method and characterized them for use in dye sensitized solar cells. Design/methodology/approach: Zinc oxide nanopowder was synthesized by using zinc acetate dehydrate as a precursor. The prepared nanopowder has been subjected to structural analysis using a transmission electron microscope (TEM). Scanning Electron Microscopic (SEM) images were taken with a Zeiss Supra 35. Qualitative studies of chemical composition were also performed using the Energy Dispersive Spectrometer (EDS). The structure of zinc oxide was investigated by X-ray crystallography The absorbance of zinc oxide layers with and without dye were measured by Thermo Scientific Evolution 220 spectrophotometer equipped with a xenon lamp in the wavelength range from 190 nm to 1100 nm. Findings: Sol-gel method allows the formation of uniform nanoparticles of zinc oxide. The nanoparticles have been successfully used in photoelectrode of dye sensitized solar cell. The light harvesting efficiency of the electrode it remains in a wide spectral range above 85%, which gives better results than in the case of titanium dioxide. Research limitations/implications: The next step in the research will be to investigate the ZnO/NiO composite on the properties of the photoelectrode of dye sensitized solar cell. Practical implications: he unique properties of produced ZnO nanostructural materials have caused their interest in such fields as medicine, transparent electronics and photovoltaics. Originality/value: The ZnO nanoparticles were prepared using sol-gel method and then effectively used in the photoanode of dye sensitized solar cell.

NiO nanoparticles prepared by thesol-gel method for a dye sensitizedsolar cell applications

Purpose: The purpose of this article is to synthesized NiO nanostructures by sol-gel method and characterized them for use in dye sensitized solar cells. For this purpose, a paste prepared from nanoparticles was prepared and screen printed on a glass substrate with the FTO layer. Design/methodology/approach: Nickel oxide nanoparticles was synthesized with participation of nickel (II) nitrate hexahydrate and citric acid. The prepared nanopowder has been subjected to structural analysis using a transmission electron microscope (TEM). Scanning Electron Microscopic (SEM) images were taken with a Zeiss Supra 35. Qualitative studies of chemical composition were also performed using the Energy Dispersive Spectrometer (EDS). The structure of nickel oxide was investigated by X-ray crystallography. An average crystallite size were calculated using Scherrer method and Williamson-Hall analysis. Light harvesting efficiency LHE was calculated from measured absorbance. Findings: The uniform nickel oxide nanoparticles with spherical shape were successfully produced by sol-gel method. The diameter of the as prepared nanoparticles does not exceed 25 nm which is confirmed by the XRD and TEM analysis. The light harvesting efficiency of the electrode in the entire studied range it’s over 90%. Therefore the NiO can be an attractive alternative to the most commonly used TiO2. Research limitations/implications: The next step in the research will be to investigate the ZnO/NiO composite on the properties of the photoelectrode of dye sensitized solar cell. Practical implications: The unique properties of produced NiO nanostructural materials have caused their interest in such fields as medicine, transparent electronics and photovoltaics. Originality/value: The NiO nanoparticles were prepared using sol-gel method and then effectively used in the photoanode of dye sensitized solar cell.

Structure and optical properties of TiO2 thin films deposited by ALD method

Abstract This paper presents the results of study on titanium dioxide thin films prepared by atomic layer deposition method on a silicon substrate. The changes of surface morphology have been observed in topographic images performed with the atomic force microscope (AFM) and scanning electron microscope (SEM). Obtained roughness parameters have been calculated with XEI Park Systems software. Qualitative studies of chemical composition were also performed using the energy dispersive spectrometer (EDS). The structure of titanium dioxide was investigated by X-ray crystallography. A variety of crystalline TiO2 was also confirmed by using the Raman spectrometer. The optical reflection spectra have been measured with UV-Vis spectrophotometry.

The structure and conductivity of polyelectrolyte based on MEH-PPV and potassium iodide (KI) for dye-sensitized solar cells

Abstract This article presents the results of a research on the effects and properties of the potassium iodide additive onto the structure of the MEH-PPV polymer material, in its aspect of application in the dye-sensitized solar cell. Changes in MEH-PPV surface morphology were researched through increasing of the potassium iodide content measured by scanning electron microscope. The increased content of potassium iodide also led to increased electrical conductivity measured by the Keithley meter. The electrical properties of the dye-sensitized solar cell were also studied, in which the liquid electrolyte was replaced with a thin layer of polyelectrolyte, based on MEH-PPV and potassium iodide.

Synthesis of Pt nanowires with the participation of physical vapour deposition

Abstract The following paper presents the possibility of formation of Pt nanowires, achieved by a three-step method consisting of conformal deposition of a carbon nanotube and conformal coverage with platinum by physical vapour deposition, followed by removal of the carbonaceous template. The characterization of this new nanostructure was carried out through scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD).