30,531 research outputs found
Blocking layer optimisation of poly(3-hexylthiopene) based Solid State Dye Sensitized Solar Cells
No full textThe optimisation study of the fabrication of a compact TiO2 blocking layer (via Spray Pyrolysis
Deposition) for poly(3-hexylthiopene) (P3HT) for Solid State Dye Sensitized Solar Cells
(SDSCs) is reported. We used a novel spray TiO2 precursor solution composition obtained
by adding acetylacetone to a conventional formulation (Diisopropoxytitanium bis(acetylacetonate)
in ethanol). By Scanning Electron Microscopy a TiO2 layer with compact morphology
and thickness of around 100 nmis shown. Through a Tafel plot analysis an enhancement of the
device diode-like behaviour induced by the acetylacetone blocking layer respect to the conventional
one is observed. Significantly, the device fabricatedwith the acetylacetone blocking
layer shows an overall increment of the cell performance with respect to the cellwith the conventional
one (DJsc/Jsc = +13.8%, DFF/FF = +39.7%, DPCE/PCE = +55.6%). A conversion efficiency
optimumis found for 15 successive spray cycles where the diode-like behaviour of the acetylacetone
blocking layer is more effective. Over three batches of cells (fabricated with P3HT and
dye D35) an average conversion efficiency value of 3.9% (under a class A sun simulator with 1
sun A.M. 1.5 illumination conditions) was measured. From the best cell we fabricated a conversion
efficiency value of 4.5% was extracted. This represents a significant increment with
respect to previously reported values for P3HT/dye D35 based SDSCs
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Azione del levobunololo sul flusso ematico retinico valutato mediante blue- field
No full textAzione del levobunololo sul flusso ematico retinico valutato mediante blue- fiel
Investigating the electrodeposition mechanism of anodically grown NiOOH films on transparent conductive oxides
No full textElectrodeposition of NiOOH is an attracting route toward nanosized films of NiO, a p-type semiconductor used in many advanced applications. In this paper, the deposition mechanism is thoroughly investigated aiming at the clarification of the deposition dynamics and the chemical nature of the deposit. We focused on initial stages of the potentiostatic deposition on ITO, which yields a nanostructured film. In the potential range investigated the process is mass transport controlled and strongly overlaps with oxygen evolution reaction. The nucleation regime, which is finely tunable, correlates with the surface extension of the film. Supporting electrolytes are found to suppress the deposition, likely by modifying the nickel speciation in the aqueous electrolyte. Further, through XPS investigation we shed light on the mixed γ−β NiOOH nature of the deposited film and its electrochemistry. This work provides precious understanding for future exploitations of anodic electrodeposited NiO, especially in applications where a strict control on surface morphology and thickness at the nanoscale level is mandatory
"Il test dell'ipobamina sulla IOP nella terapia antiflogistica con clobetasone".
No full textEffetti del test dell'ipobamina sulla IOP nella terapia antiflogistica con clobetason
Elaboration on Kwapien's theorem: Representing bounded mean zero functions f as coboundary f = g ◦ T − g
No full textIn [8] Kwapien proved that every mean zero function f ∈ L∞[0, 1] we can write as f = g ◦ T − g for some g ∈ L∞[0, 1] and some measure preserving transformation T of [0, 1]. However, as was discovered in [4] there is a gap in the proof for the case that f is not continuous. The aim of this bachelor thesis is filling in that gap in the proof. We first extend Kwapien’s proof for continuous functions to certain other measure spaces. Thereafter, we use the method of proof suggested by Kwapien, to proof the theorem for mean zero function f ∈ L∞[0, 1] for which λ(f−1({x})) = 0 for all x ∈ R. Using this result we then proof that every mean zero function f ∈ L∞[0, 1] can be written as a sum f =(g1 ◦ T1 − g1) + (g2 ◦ T2 − g2) where g1, g2 ∈ L∞[0, 1] and where T1, T2 are measure preserving transformations of [0, 1]. We finish this thesis with an application of Kwapien’s theorem in the study to singular traces Applied Mathematic
Elemental Mapping of Perovskite Solar Cells by Using Multivariate Analysis: An Insight into Degradation Processes.
No full textThe technology of perovskite-based solar cells is evolving rapidly, reaching certified power conversion efficiency values now exceeding 20 %. One of the main drawbacks hindering progress in the field is the long-term stability of the cells: the mixed halide perovskites used in most devices are sensitive to humidity and degrade on a timescale varying from hours to weeks. The degradation mechanisms are poorly understood, but likely arise from combined physical and chemical modifications at the nanometer scale. The characterization of pristine and degraded materials is difficult owing to their complex chemical and physical structure and their relatively poor stability. In this work, we investigated the changes in local composition and morphology of a standard device after 2 months of air exposure in the dark, using scanning transmission electron microscopy (STEM) with nanometer resolution for imaging and analysis. Because of a state-of-the-art technique that combines STEM and energy dispersive X-ray spectroscopy (EDX), and the use of different decomposition algorithms for multivariate analysis, we highlighted the migration of elements across the interfaces between the layers comprising the device. We also noticed a morphological degradation of the hole-transporting layer (HTL), representing one of the main factors enabling the infiltration of moisture in the device, which results in reduced performance
Timololo maleato e dipivalilepinefrina : sinergismo nel trattamento del glaucoma ad angolo aperto
No full textUnveiling the Chemical Composition of Halide Perovskite Films Using Multivariate Statistical Analyses
No full textThe local chemical composition of halide perovskites is a crucial factor in determining their macroscopic properties and their stability. While the combination of scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDX) is a powerful and widely used tool for accessing such information, electron-beam-induced damage and complex formulation of the films make this investigation challenging. Here we demonstrate how multivariate analysis, including statistical routines derived from “big data” research, such as principal component analysis (PCA), can be used to dramatically improve the signal recovery from fragile materials. We also show how a similar decomposition algorithm (non-negative matrix factorisation (NMF)) can unravel elemental composition at the nanoscale in perovskite films, highlighting the presence of segregated species and identifying the local stoichiometry at the nanoscale
In situ observation of heat-induced degradation of perovskite solar cells
No full textThe lack of thermal stability of perovskite solar cells is hindering the progress of this technology towards adoption in the consumer market. Different pathways of thermal degradation are activated at different temperatures in these complex nanostructured hybrid composites. Thus, it is essential to explore the thermal response of the mesosuperstructured composite device to engineer materials and operating protocols. Here we produce devices according to four well-established recipes, and characterize their photovoltaic performance as they are heated within the operational range. The devices are analysed using transmission electron microscopy as they are further heated in situ, to monitor changes in morphology and chemical composition. We identify mechanisms for structural and chemical changes, such as iodine and lead migration, which appear to be correlated to the synthesis conditions. In particular, we identify a correlation between exposure of the perovskite layer to air during processing and elemental diffusion during thermal treatment
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