PREPARATION AND CHARACTERIZATION OF POLY-CRYSTALLINE SILICON THIN FILM

Poly-crystalline silicon thin film has big potential of reducing the cost of solar cells. In this paper the preparation of thin film is introduced, and then the morphology of poly-crystalline thin film, is discussed. On the film we developed poly-crystalline silicon thin film solar cells with efficiency up to 6.05% without anti-reflection coating.

Nano-crystallites Imine-based Copper(II) Complexes as Mimetics for Copper Oxidase Proteins: Synthesis,Characterization,DFT and Oxidase Mimicking Activity

Three tridentate imine ligands containing N2S donors were synthesized via Schiff condensation between derivatives of both amino triazine and 2-carbonyl pyridine.The reaction of these ligands with CuCl2 in a molar ratio of 1:1 provides three Cu(II) complexes with the general formula [CuLn·Cl_(2)].Analytical,electrical,magnetic,and spectroscopic studies were used to assign the molecular formulae of these metallic chelates.Density function theory (DFT) calculations confirmed the structural analysis results obtained from spectroscopic studies.The various characterization techniques used demonstrated the penta-coordinated slightly distorted square pyramidal structure for the present Cu(II) complexes 1,2,and 3.Measurements of cyclic voltammetry were done in methanol to define the electrochemical behavior of the current Cu(II) complexes.The biomimetics of catechol oxidase (C.O.);phenoxazinone synthase (PHS) have been studied in the aerobic oxidation of some phenolic substrates,such as 3,5-di-tert-butylcatechol (3,5-DTBCH2);ortho-aminophenol (o-APH3).The three candidate oxidase mimetics showed promising activity in the order 3 > 1 > 2.The catalytic activity related to the structural properties of existing oxidase mimetics was discussed.The driving force (-ΔG°) controlling the redox reactions of the present biomolecules was calculated from the redox data of Cu(II) complexes 1,2,and 3.The potential catalytic reaction pathway for the oxidation of the studied phenolic substrates was discussed.

A Novel Route to Synthesize Nano-crystalline Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O(3-δ) Perovskite Oxide at High Temperature

It is normally difficult to prepare nano-sized Ba0.5Sr0.5Co0.8Fe0.2O3-δ（BSCF） oxide at high temperature due to its high surface activity. The complexing process, which has successfully applied in the synthesis of nano Sm0.15Ce0.85I1.925 with crystallite size down to 5 nml, just resulted in a coarse BSCF with crystaUite size of 41.9 nm at 900℃. We applied a novel process by simply modifying the solid precursor from the complexing process with concentrated nitric acid treatment. The obtained BSCF powder had a crystaUite size of -25 nm even calcined at 1000℃. The small crystaUite size is extremely promising to enhance the electrochemical performance of cathode for solid oxide fuel cell dramatically.

Drastic Resistivity Reduction of CVD-TiO₂Layers by Post-Wet-Treatment in HCl Solution

Poly-crystalline anatase TiO2 layer fabricated by LPCVD using titanium-tetra-iso-propoxide and NbF5 in H2-ambient was treated in conc.-HCl solution after thin layer of IIIb-group metal was deposited on the TiO2 layer. Resistivity of the as-deposited layer about 1 × 10-1 Ω·cm was drastically reduced to 3 × 10-3 Ω·cm by the wet-treatment using indium. Temperature dependence of the resistivity increased with temperature above 100 K for the wet-treated layer was quite different from that decreased above 100 K for the as-deposited layer, whereas the resistivity was saturated at lower temperatures. The resistivity at room-temperature was decreased with the thickness before the wet-treatment but independent on the thickness above 100 nm for the wet-treated layer. Indium was more effective for the resistivity reduction than gallium but aluminum was not useful for the treatment. As the results that the wet-treatment using indium was examined for the TiO2 layers deposited by various conditions, the optimum deposition condition to reduce the resistivity of the layer after the wet-treatment was clearly different from that for the as-deposited layer.

Quantifying the effectiveness of SiO_2/Au light trapping nanoshells for thin film poly-Si solar cells

In order to enhance light absorption of thin film poly-crystalline silicon(TF poly-Si)solar cells over a broad spectral range, and quantify the effectiveness of nanoshell light trapping structure over the full solar spectrum in theory,the effective photon trapping flux(EPTF)and effective photon trapping efficiency(EPTE)were firstly proposed by considering both the external quantum efficiency of TF poly-Si solar cell and scattering properties of light trapping structures.The EPTF,EPTE and scattering spectrum exhibit different behaviors depending on the geometric size and density of nanoshells that form the light trapping layer.With an optimum size and density of SiO2/Au nanoshell light trapping layer,the EPTE could reach up to 40%due to the enhancement of light trapping over a broad spectral range,especially from 500 to 800 nm.

Technical aspect for oxidation of magnesium and aluminum nitrates to manufacture nano- and micro-sized MgAl2O4 spinel by combustion method

In the present investigation, the nano- and micro-sized powders were synthesized by stoichiometric contents of magnesium and aluminum nitrates using combustion–oxidation method. The study was conducted over a wide range of operating conditions, in terms of fuel ratio and calcination temperature. The characteristics of magnesium aluminate powders were studied by differential thermal analysis and thermogravimetry (DTA–TG), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The thermal stability of powders was evaluated by calcination at different temperatures. Differences of the specific surface areas were related to the composition and crystallite size. The importance of fuel ratio and calcination temperature to achieve the nano- and micro-sized oxide was discussed in detail. The fuel ratio of 0.56 and calcination at 800 ℃ provided the conditions to achieve the nano-scale magnesium aluminate powders, smaller than 20 nm. The application of presented algorithm can be an important tool for control of particle size in the nano- and micro-scale.