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In this paper we report on the single stage deposition of CuInxGa1−xSe2 (CIGS)-based bifacial solar cells on glass coated with Fluorine-doped Tin Oxide (FTO) or Indium Tin Oxide (ITO) by single-stage low-temperature (250 °C) pulsed electron deposition (LTPED). We show that the mechanism of Sodium incorporation during the low-temperature deposition of CIGS on both FTO and ITO leads to the formation of a stable n+/p+ ohmic tunnel junction and photovoltaic efficiencies exceeding 14% can be obtained without any intentional bandgap grading of CIGS. The significant degradation of the cell fill factor with decreasing CIGS thickness is found to be related to the presence of craters left behind by micro-fragments of CIGS target, which are weakly incorporated in the film during the LTPED growth and removed during the subsequent process steps. Evidence is also presented that the low-temperature deposition of CIGS on ITO leads to the formation of a Ga-rich CIGS layer at the interface and to an unintentional compositional grading propagating towards the active region of the solar cells. The defects associated with this grading may be responsible for the loss in FF and Voc with respect to the cells deposited on FTO and Mo back contacts.

In this study, a comparison between Al-doped ZnO (AZO) as Transparent Conductive Oxide for Cu(In,Ga)Se-2-based solar cells grown by Pulsed Electron Deposition (PED) and Radio Frequency Magnetron Sputtering (RFMS) was performed. PED yielded polycrystalline [002] mono-oriented thin films with low electrical resistivity and high optical transparency with heater temperatures ranging from room temperature (RT) to 250 degrees C. The electrical resistivity of these films can be tuned by varying the heater temperature, reaching a minimum value of 3.5 x 10(-4) Omega cm at 150 degrees C and an average transmittance over 90% in the visible range. An AZO film grown at RT was deposited by PED on an actual Cu(In,Ga)Se-2-based solar cell, resulting to an efficiency value of 15.2% on the best device. This result clearly shows that PED is a suitable technique for growing ZnO-based thin films for devices/applications where low deposition temperature is required. On the other hand, an optimized AZO thin film front contact for thin film solar cells was studied and fabricated via RFMS. The parameters of this technique were tweaked to obtain highly conductive and transparent AZO thin films. The lowest resistivity value of 3.7 x 10(-4) Omega cm and an average transmittance of 86% in the 400-1100 nm wavelength range was obtained with a heater temperature of 250 degrees C. A thick sputtered AZO film was deposited at RT onto an identical cell used for PED-grown AZO, reaching the highest conversion efficiency value of 14.7%. In both cases, neither antireflection coatings nor pure ZnO layer was used. (C) 2014 Elsevier B.V. All rights reserved.

Zero-field μ SR experiments were performed on a series of polycrystalline samples of AA 3 ′ Mn 4 O 12 double perovskites ( A = Na + , Ca 2 + , La 3 + ; A ′ = Cu 2 + , Mn 3 + ) synthesized under high pressure. Spontaneous precession frequencies, of comparable magnitude to those previously reported in LaMnO 3 , were observed in all the family members except CaMn 7 O 12 . For all the samples, μ SR yielded determinations of the magnetic transition temperatures and of the order parameter in agreement with other techniques, but also revealed a peculiar phase separation in CaMn 7 O 12 , absent in the other compounds.

The level of an Fe-doped InP melt in a growth crucible is kept constant throughout a Czochralski growth experiment by replenishing it with undoped melt from a second crucible. Since the distribution coefficient of iron is very small (about 0.001), the Fe concentration in the growth crucible is virtually unchanged during the pulling. As a result the ingot obtained exhibits axial Fe concentration much more uniform than in standard LEC crystals. This growth method can increase the yield of semi-insulating InP wafers as it prevents the accumulation of iron and the formation of precipitates in the last to freeze part of the crystal.

The immobilization of a commercial preparation of pectinlyase (PL, EC 4.2.2.3) derived from Aspergillus niger was studied in view of its possible application in fruit juice treatments. Pectinlyase is an enzyme that is subject to growing interest for the substitution of other pectic enzymes: e.g., polygalacturonase (EC 3.2.1.15) and pectinesterase (EC 3.1.1.11). The PL was immobilized by physical adsorption or by the formation of covalent bonds on organic (cellulose and its derivatives, XAD-amberlites) and inorganic (sulphides, γ-alumina, and bentonite) supports. The supports that permitted an effective immobilization with good activity levels and sufficient stability under the operational conditions were found to be the acrylic resin XAD 7 activated with trichlorotriazine and, in particular, bentonite activated with glutaraldehyde.

Freezing point depression and some physical characteristics of Vitis vinifera grapes var. Ancellotta were investigated after two different post-harvest treatments of samples (slow air-freezing at −18°C and storage at 2°C in N 2 atmosphere). The measured acinus mean weight and diameter, relative weight composition of a cluster and total soluble solids content differed slightly from those of fresh grapes. The observed freezing point depression values for treated grapes and grape juice were smaller than the respective calculated data. The differences were characterized by alteration in soluble solids composition due to the treatments, which decreased solute-solvent interactions.