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Abstract: We report on the electrical and physical properties of Cu2ZnSnSe4 (CZTSe) solar cells consisting of an absorber layer fabricated by selenization of sputtered Cu, Zn, Sn multilayers. Cross-section scanning electron microscopy images show that the polycrystalline absorber layers are approximately 1μm thick and that the typical grain size is of the order of 1μm. Energy-dispersive X-ray spectroscopy measurements show Cu-poor and Zn-rich compositions with Cu/(Zn+Sn)~0.8 and Zn/Sn~1.2. Solar cells are fabricated out of this absorber material using a standard process flow for chalcogenide solar cells. Under AM1.5G illumination, the best 1×1cm2 CZTSe solar cell shows an efficiency of 6.3% with a maximum short circuit current of 31.3mA/cm2, an open circuit voltage of 0.39V and a fill factor of 52%. Doping density of the absorber layers is derived using the drivel level capacitance profiling (DLCP) technique, showing low p-type doping density which seems to increase exponentially with the Zn/Sn ratio. Comparing the values obtained from DLCP to the ones derived from Mott–Schottky plots of the same devices, it is shown that for CZTSe care has to be taken when deriving the doping density. Similar to copper indium gallium selenide junctions, Mott–Schottky plots overestimate the amount of free carriers in the buffer due to the presence of fast defect states inside the bandgap. [Copyright &y& Elsevier]

Abstract: Sulfonated polysulfones (SPSF) with different sulfonation degrees were prepared by reaction of polysulfone with chlorosulfonic acid. The honeycomb films were fabricated by the breath figure method from freshly prepared SPSF/chloroform solutions. Furthermore, using the ordered porous SPSF films as template, honeycomb polyaniline (PANI) composite films were prepared by a simple one-step chemical oxidation polymerization of aniline. The surface morphology and conductivity of the PANI/SPSF composite film were characterized by environmental scanning electron microscopy and four-probe technique, respectively. The results indicate that the SPSF honeycomb ordered film played the role as template in controlling the morphology of the PANI/SPSF composite film with the porous and electrically conductive surface. [Copyright &y& Elsevier]