30 research outputs found

    Enhanced stability of perovskite solar cells incorporating dopant-free Crystalline spiro-OMeTAD layers by vacuum sublimation

    Get PDF
    The main handicap still hindering the eventual exploitation of organometal halide perovskite-based solar cells is their poor stability under prolonged illumination, ambient conditions, and increased temperatures. This article shows for the first time the vacuum processing of the most widely used solid-state hole conductor (SSHC), i.e., the Spiro-OMeTAD [2,2â€Č,7,7â€Č-tetrakis (N,N-di-p-methoxyphenyl-amine) 9,9â€Č-spirobifluorene], and how its dopant-free crystalline formation unprecedently improves perovskite solar cell (PSC) stability under continuous illumination by about two orders of magnitude with respect to the solution-processed reference and after annealing in air up to 200 °C. It is demonstrated that the control over the temperature of the samples during the vacuum deposition enhances the crystallinity of the SSHC, obtaining a preferential orientation along the π–π stacking direction. These results may represent a milestone toward the full vacuum processing of hybrid organic halide PSCs as well as light-emitting diodes, with promising impacts on the development of durable devices. The microstructure, purity, and crystallinity of the vacuum sublimated Spiro-OMeTAD layers are fully elucidated by applying an unparalleled set of complementary characterization techniques, including scanning electron microscopy, X-ray diffraction, grazing-incidence small-angle X-ray scattering and grazing-incidence wide-angle X-ray scattering, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy.The authors thank the “Agencia Estatal de InvestigaciĂłn”, “ConsejerĂ­a de EconomĂ­a y Conocimiento de la Junta de AndalucĂ­a” (US‐1263142), “Ministerio de EconomĂ­a y Competitividad” (MAT2016‐79866‐R, MAT2013‐42900‐P, FPA2016‐77689‐C2‐1‐R, and MAT2016‐76892‐C3‐2‐R) and the European Union (EU) through cohesion fund and FEDER 2014‐2020 programs for financial support. J.R.S.‐V. and A.B. acknowledge the EU project PlasmaPerovSol and funding from the European Union's Horizon 2020 research and innovation programme under the Marie SkƂodowska‐Curie grant agreement ID 661480. J.R.S.‐V‐ and M.C.L.‐S. thank the University of Seville through the VI “Plan Propio de InvestigaciĂłn y Transferencia de la US” (VI PPIT‐US). This research has received funding from the EU‐H2020 research and innovation programme under Grant Agreement No. 654360 having benefitted from the access provided by Technische UniversitĂ€t Graz at Elettra—TUG in Trieste (IT) within the framework on the NFFA (Nanoscience Foundries & Fine Analysis) Europe Transnational Access Activity. F.J.A. and J.R.S.‐V. acknowledge the “Juan de la Cierva” and “Ramon y Cajal” national programs, respectively

    Low temperature plasma processing of platinum porphyrins for the development of metal nanostructured layers

    Get PDF
    This article establishes the bases for a vacuum and plasma supported methodology for the fabrication at mild temperatures of nanostructured platinum in the form of porous layers and nanocolumns using platinum octaethylporphyrin as precursor. In addition, the application of these materials as tunable optical filters and nano-counterelectrodes is proved. On one hand, the transparency in the ultraviolet-visible-near infrared range can be adjusted precisely between 70% and 1% by tuning the deposition and processing conditions, obtaining a high spectral planarity. Deviations of the spectra from an ideal flat filter are below 4%, paving the way to the fabrication of neutral density filters. The transparency limit values yield a sheet resistivity of ¿1350 and 120 ¿ ¿-1, respectively. On the other hand, the catalytic properties of the nanostructures are further demonstrated by their implementation as counterelectrodes of excitonic solar cells surpassing the performance of commercial platinum as counterelectrode in a 20% of the overall cell efficiency due to simultaneous enhancement of short-circuit photocurrent and open-circuit photovoltage. One of the most interesting features of the developed methodology is its straightforward application to other metal porphyrins and phthalocyanines readily sublimable under mild vacuum and temperature conditions.Junta de AndaluciaTEP8067 FQM-6900 FQM 1851 P12-FQM-2265España MinecoMAT2013-40852-R MAT2013-42900-P MAT2013-47192-C3-3-RMAT2016-79866-RMINECO-CSIC 201560E055

    Development of educational materials for chronic patients and families

    Get PDF
    Low literacy can difficult the use of information needed to take appropriate decisions in healthcare. This situation is associated with poorer treatment adherence, lower health outcomes and higher mortality among the population and, specifically, the elderly. It is essential that information can be understood by patients and families. This article aims to present the existing international recommendations for the design and development of educational materials and resources to chronic patients and families. This process encompasses the involvement of patients at various levels during the development process of the materials, the adaptation of the format and content to the level of understanding of the patient as well as their participation in the evaluation process. Educational materials that have been developed in collaboration with patients are more adapted to their context and promote positive changes in their health

    Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota)

    Get PDF
    Compared to the higher fungi (Dikarya), taxonomic and evolutionary studies on the basal clades of fungi are fewer in number. Thus, the generic boundaries and higher ranks in the basal clades of fungi are poorly known. Recent DNA based taxonomic studies have provided reliable and accurate information. It is therefore necessary to compile all available information since basal clades genera lack updated checklists or outlines. Recently, Tedersoo et al. (MycoKeys 13:1--20, 2016) accepted Aphelidiomycota and Rozellomycota in Fungal clade. Thus, we regard both these phyla as members in Kingdom Fungi. We accept 16 phyla in basal clades viz. Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. Thus, 611 genera in 153 families, 43 orders and 18 classes are provided with details of classification, synonyms, life modes, distribution, recent literature and genomic data. Moreover, Catenariaceae Couch is proposed to be conserved, Cladochytriales Mozl.-Standr. is emended and the family Nephridiophagaceae is introduced

    Impact of moisture on efficiency-determining electronic processes in perovskite solar cells

    No full text
    Moisture-induced degradation in perovskite solar cells was thoroughly investigated by structural (SEM, EDS, XRD and XPS) and device characterization (impedance and intensity modulated photocurrent spectroscopy) techniques. Both the influence of the perovskite composition and the nature of the hole selective material were analyzed. The degradation rate was found to be significantly slower for mixed perovskites and P3HT-based devices. However, for a fixed degradation degree (defined as a 50% drop from the initial photocurrent), all configurations show similar features in small-perturbation analysis. Thus, a new mid-frequency signal appears in the impedance response, which seems to be related to charge accumulation at the interfaces. In addition, faster recombination, with a more important surface contribution, and slower transport were clearly inferred from our results. Both features can be associated with the deterioration of the contacts and the formation of a higher number of grain boundaries.We thank Junta de Andalucía for financial support via grant FQM 1851 and FQM 2310. We thank the Ministerio de Economía y Competitividad of Spain (MAT2013-47192-C3-3-R and MAT2016-76892-C3-2-R) and the EU through the Cohesion Fund and FEDER programs (MAT2013-42900-P and MAT2016-79866-R) for financial support and Red de Excelencia “Emerging photovoltaic Technologies”. SA and LC are thankful for the “Thinface” project from the European Union Seventh Framework Programme, under grant agreement no. 607232, for financial support.Peer reviewe

    A large bridge pier in an alluvial channel: local scour versus morphological effects and the role of physical models

    No full text
    This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29HY.1943-7900.0001993The large pier of an emblematic bridge built in 2008 in the Ebro River (Zaragoza, Spain) obstructs the flow in high floods. Clear-water scour experiments in a scale model were conducted to anticipate maximum local scour depths and design riprap protections. These proved to be effective during a large flood event in 2015, but bed aggradation under the left bridge span and deep scour under the right one, not mirroring the bed deformation observed in the model, raised concerns about the bridge safety. The effects of the protected pier on the changes in the aftermath of the 2015 flood are discussed. It is shown that a large meander upstream generated an imbalance in the spanwise bedload distribution, leading to sedimentation on the left and contraction scour on the right. The paper argues for the need to take into account the effects of large piers on river morphology at the bridge planning phase. The case study shows that using a clear-water model to design the riprap protection is adequate, but more importantly, that the fluvial processes during a flood could only be studied with a live-bed model with geometrical detail of the full river reach, namely, the upstream meander.Thanks to the insightful, helpful comments by the Associate Editor. Thanks to the Ebro Water Authority (Marisa Moreno and Miriam Pardos) and Zaragoza Municipality (Luis Manso) for providing hydrological data and field surveys. We also thank the financial support of the FEDER-COMPETE2020 (POCI) and Portuguese funds (Foundation for Science and Technology, IP) through project PTDC/ECI-EGS/29835/2017—POCI-01-0145-FEDER-029835.Peer ReviewedPostprint (published version

    Hydrophobicity, freezing delay, and morphology of laser-treated aluminum surfaces

    No full text
    Until recently, superhydrophobicity was considered as a hint to predict surface icephobicity, an association of concepts that is by no means universal and that has been proven to depend on different experimental factors and material properties, including the actual morphology and chemical state of surfaces. This work presents a systematic study of the wetting and freezing properties of aluminum Al6061, a common material widely used in aviation, after being subjected to nanosecond pulsed IR laser treatments to modify its surface roughness and morphology. All treated samples, independent of their surface finishing state, presented initially an unstable hydrophilic wetting behavior that naturally evolved with time to reach hydrophobicity or even superhydrophobicity. To stabilize the surface state and to bestow the samples with a permanent and stable hydrophobic character, laser-treated surfaces were covered with a thin layer of CFx prepared by plasma-enhanced chemical vapor deposition. A systematic comparison between freezing delay (FD) and wetting properties of water droplets onto these plasma-/polymer-modified laser-treated surfaces that, under conditions where a heterogeneous nucleation mechanism prevails, surface morphology rather than the actual value of the surface roughness parameter the key feature for long FD times. In particular, it is found that surface morphologies rendering a Cassie–Baxter wetting regime longer FDs than those characterized by a Wenzel-like wetting state. It is that laser treatment, with or without additional coverage with thin CFx coatings, affects wetting and ice formation behaviors and might be an efficient procedure to mitigate icing problems on metal surfaces.This work has been carried out with the support of the EU project PHOBIC2ICE (ref 690819). The authors also thank the European Regional Development Funds program (EU-FEDER) and the MINECO-AEI (201560E055 and MAT2016-79866-R and network MAT2015-69035-REDC) for financial support.Peer reviewe

    Low-Temperature Plasma Processing of Platinum Porphyrins for the Development of Metal Nanostructured Layers

    No full text
    This article establishes the bases for a vacuum and plasma supported methodology for the fabrication at mild temperatures of nanostructured platinum in the form of porous layers and nanocolumns using platinum octaethylporphyrin as precursor. In addition, the application of these materials as tunable optical filters and nano-counterelectrodes is proved. On one hand, the transparency in the ultraviolet-visible-near infrared range can be adjusted precisely between 70% and 1% by tuning the deposition and processing conditions, obtaining a high spectral planarity. Deviations of the spectra from an ideal flat filter are below 4%, paving the way to the fabrication of neutral density filters. The transparency limit values yield a sheet resistivity of Âż1350 and 120 Âż Âż-1, respectively. On the other hand, the catalytic properties of the nanostructures are further demonstrated by their implementation as counterelectrodes of excitonic solar cells surpassing the performance of commercial platinum as counterelectrode in a 20% of the overall cell efficiency due to simultaneous enhancement of short-circuit photocurrent and open-circuit photovoltage. One of the most interesting features of the developed methodology is its straightforward application to other metal porphyrins and phthalocyanines readily sublimable under mild vacuum and temperature conditions.Peer Reviewe
    corecore