Examinando por Autor "Lazo, Pamela"

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    Assessment of Native and Endemic Chilean Plants for Removal of Cu, Mo and Pb from Mine Tailings
    (MDPI, 2020) Lazo, Pamela; Lazo, Andrea
    In Chile, 85% of tailings impoundments are inactive or abandoned and many of them do not have a program of treatment or afforestation. The phytoremediation of tailings with Oxalis gigantea, Cistanthe grandiflora, Puya berteroniana and Solidago chilensis have been tested in order to find plants with ornamental value and low water requirements, which enable reductions in molybdenum (Mo), copper (Cu) or lead (Pb) concentrations creating an environmentally friendly surrounding. Ex-situ phytoremediation experiments were carried out for seven months and Mo, Cu and Pb were measured at the beginning and at the end of the growth period. The capacity of these species to phyto-remedy was evaluated using the bioconcentration and translocation factors, along with assessing removal efficiency. Solidago chilensis showed the ability to phytoextract Mo while Puya berteroniana showed potential for Cu and Mo stabilization. The highest removal efficiencies were obtained for Mo, followed by Cu and Pb. The maximum values of removal efficiency for Mo, Cu and Pb were 28.7% with Solidago chilensis, 15.6% with Puya berteroniana and 8.8% with Cistanthe grandiflora, respectively. Therefore, the most noticeable results were obtained with Solidago chilensis for phytoextraction of Mo.
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    Electrochemically Assisted Growth of CsPbBr3-Based Solar Cells Without Selective Contacts
    (European Chemical Societies Publishing, 2020) Ramírez, Daniel; Riveros, Gonzalo; Díaz, Patricia; Verdugo, Javier; Núñez, Gerard; Lizama, Susy; Lazo, Pamela; Contreras-Bernal, Lidia; Riquelme, Antonio; Idigoras, Jesús; Dalchiele, Enrique A.; Gau, Daniel L.; Marotti, Ricardo E.; Anta, Juan A.
    In this work we report a simple and cost-effective CsPbBr3- based solar cell without ordinary selective contacts. To do so we follow an electrochemical approach consisting of three successive steps: (1) electrodeposition of PbO2 directly on top of FTO substrates, (2) heterogeneous phase reaction with gaseous HBr and (3) spin-coating of methanolic CsBr solutions followed by annealing. This method is more adequate for large- scale environmentally friendly production as it reduces chemical waste, particularly toxic lead. The resulting films were structurally and optically characterized showing good coverage of the FTO substrates, absence of defects such as pinholes and orthorhombic structure. Photovoltaic and impedance characterization was carried out by pressing a carbon coated metal spring onto the CsPbBr3 film until obtaining maximized opencircuit potential (Voc) and short-circuit photocurrent density (jsc) under simulated sunlight. The stabilized current at fixed voltage (SCFV) technique gave a maximum PCE value of 2.70% close to devices with similar configuration. Impedance measurements demonstrated analogous behavior to that of state-of-art CsPbBr3 based solar cells, comprising a recombination arc at midhigh frequencies, geometrical capacitance and ideality factors closed to 2, typical of SRH recombination in the perovskite bulk.