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We report the results of an extensive study employing numerous methods to characterize carrier transport within copper indium gallium sulfoselenide (CIGSS) photovoltaic devices, whose absorber layers were fabricated by diverse process methods in multiple laboratories. This collection of samples exhibits a wide variation of morphologies, compositions, and solar power conversion efficiencies. An extensive characterization of transport properties is reported here -including those derived from capacitance-voltage, admittance spectroscopy, deep level transient spectroscopy, time-resolved photoluminescence, Auger emission profiling, Hall effect, and drive level capacitance profiling. Data from each technique were examined for correlation with device performance, and those providing indicators of related properties were compared to determine which techniques and interpretations provide credible values for transport properties. Although these transport properties are not sufficient to predict all aspects of current-voltage characteristics, we have identified specific physical and transport characterization methods that can be combined using a model-based analysis algorithm to provide a quantitative prediction of voltage loss within the absorber. The approach has potential as a tool to optimize and understand device performance irrespective of the specific

This study was to investigate the kinetics of drug release from polymer/TiO2 nanotubes composite. Lidocaine and carprofen were selected as model drugs to represent weak base and weak acid drugs, respectively. Mathematical models used to fit the in vitro drug release experimental data indicate that at higher pH, the drug release was first order diffusion controlled. At lower pH, the release of the two drugs exhibits two staged controlled release mechanism. The first phase is due to drug diffusion and the second stage is a result of poly(lactic‐co‐glycolic acid) (PLGA) polymer degradation. The rate of drug release from polymer/TiO2 nanotubes drug carrier was mainly controlled by three pH dependent factors: the solubility of the drug, the degree of polymer swelling/degradation, and the electrostatic force between polymer and drug. This study suggests that controlled release could be achieved for polymer/TiO2 nanotubes drug carrier via the modulation of pKa values of polymers and drug solubility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41570.

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This work reports a solution-based approach to grow high-density vertically aligned ZnO rod arrays with a multistage terrace structure (HDVAMT) on Au nanoparticle covered glass substrates. The solar cell performance of HDVAMT is 10 times better than that of the disordered ZnO due to the much higher short circuit current (J sc ). This significant improvement of J sc is attributed to two factors: the vertically aligned structure, which provides smoother electron transport channels, and the high density of the rods with the multistage terrace structure, which provides a higher surface area for the dye adsorption. A tentative growth mechanism is proposed.