The
employment of 2D perovskites is a promising approach to tackling
the stability and voltage issues inherent in perovskite solar cells.
It remains unclear, however, whether other perovskites with different
dimensionalities have the same effect on efficiency and stability.
Here, we report the use of quasi-3D azetidinium lead iodide (AzPbI3) as a secondary layer on top of the primary 3D perovskite
film that results in significant improvements in the photovoltaic
parameters. Remarkably, the utilization of AzPbI3 leads
to a new passivation mechanism due to the presence of surface dipoles
resulting in a power conversion efficiency (PCE) of 22.4%. The open-circuit
voltage obtained is as high as 1.18 V, which is among the highest
reported to date for single junction perovskite solar cells, corresponding
to a voltage deficit of 0.37 V for a band gap of 1.55 eV.
A method based on application of ZnO nanorods loaded on activated carbon (ZnO-NRs-AC) for adsorption of Bromocresol Green (BCG) and Eosin Y (EY) accelerated by ultrasound was described. The present material was synthesized under ultrasound assisted wet-chemical method and subsequently was characterized by FE-SEM, TEM, BET and XRD analysis. The extent of contribution of conventional variables like pH (2.0-10.0), BCG concentration (4-20mgL(-1)), EY concentration (3-23mgL(-1)), adsorbent dosage (0.01-0.03g), sonication time (1-5min) and centrifuge time (2-6min) as main and interaction part were investigated by central composite design under response surface methodology. Analysis of variance (ANOVA) was adapted to experimental data and guide the best operational conditions mass by set at 6.0, 9mgL(-1), 10mgL(-1), 0.02g, 4 and 4min for pH, BCG concentration, EY concentration, adsorbent dosage, sonication and centrifuge time, respectively. At these specified conditions dye adsorption efficiency was higher than 99.5%. The suitability and well prediction of optimum point was tested by conducting five experiments and respective results revel that RSD% was lower than 3% and high quality of fitting was confirmed by t-test. The experimental data were best fitted in Langmuir isotherm equation and the removal followed pseudo second order kinetics. The experimentally obtained maximum adsorption capacities were estimated as 57.80 and 61.73mgg(-1) of ZnO-NRs-AC for BCG and EY respectively from binary dye solutions. The mechanism of removal was explained by boundary layer diffusion via intraparticle diffusion.
The Fe2O3/CuFe2O4/chitosan nanocomposites have been successfully synthesized via a new sol-gel autocombustion route. To prepare the nanocomposites, copper ferrite (CuFe2O4) and iron (II) oxide (Fe2O3) nanostructures were first prepared utilizing onion as a green reductant for the first time, and characterized by SEM, TEM, XRD, IR and VSM. Then chitosan was added into the nanostructures dispersed in water. Chitosan was used to functionalize and modify the nanostructures and also to improve surface properties. The nanocomposites were also characterized by several techniques including SEM, TEM, XRD, IR and VSM. The effects of amount of onion and chitosan on the morphology and particle size of nanocomposites were evaluated.
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