815 research outputs found

    Depois de ziguezaguear entre os extremos, finalmente senso comum? Bélgica retornará às regras razoáveis sobre ilicitude probatória?

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    In the absence of statutory rules on the matter, Belgian courts traditionally applied a strict exclusionary rule for illegally gathered evidence and its fruits. The Court of Cassation in 2003 made a spectacular U-turn and prohibited exclusion of illegally obtained evidence by criminal courts, with only very limited exceptions. Parliament subsequently incorporated these judge-made principles into a binding statutory rule. As a new Code is about to be debated in Parliament, the time is right to question the “normalisation†of law enforcement officers’ disrespect for the rules. The Rule of Law will be restored by making exclusion of illegally gathered evidence the rule, but exceptionally allowing its use upon consideration of the conflicting interests.Diante da omissão de normas sobre a questão, as cortes belgas tradicionalmente aplicavam regras rígidas de exclusão de provas obtidas ilegalmente e suas derivadas. A Corte de Cassação em 2003 alterou drasticamente tal posição e proibiu os tribunais de excluir as provas ilícitas, salvo exceções bastante limitadas. O Legislativo então incorporou esses princípios em uma regra legal obrigatória. Considerando os debates legislativos sobre um novo código, o momento é adequado para discutir a normalização do desrespeito às regras pelos agentes estatais. O Estado de Direito será restaurado com a consolidação da regra de exclusão das provas ilícitas, mas com a possibilidade de utilização excepcional a partir de ponderação de conflito de interesses

    High-performance flexible perovskite solar cells exploiting Zn2SnO4 prepared in solution below 100 degrees C

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    Fabricating inorganic-organic hybrid perovskite solar cells (PSCs) on plastic substrates broadens their scope for implementation in real systems by imparting portability, conformability and allowing high-throughput production, which is necessary for lowering costs. Here we report a new route to prepare highly dispersed Zn2SnO4 (ZSO) nanoparticles at low-temperature (<100 degrees C) for the development of high-performance flexible PSCs. The introduction of the ZSO film significantly improves transmittance of flexible polyethylene naphthalate/indium-doped tin oxide (PEN/ITO)-coated substrate from similar to 75 to similar to 90% over the entire range of wavelengths. The best performing flexible PSC, based on the ZSO and CH3NH3PbI3 layer, exhibits steady-state power conversion efficiency (PCE) of 14.85% under AM 1.5G 100 mW . cm(-2) illumination. This renders ZSO a promising candidate as electron-conducting electrode for the highly efficient flexible PSC applications.ope

    Organic gelators as growth control agents for stable and reproducible hybrid perovskite-based solar cells

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    Low molecular-weight organic gelators are widely used to influence the solidification of polymers, with applications ranging from packaging items, food containers to organic electronic devices, including organic photovoltaics. Here, this concept is extended to hybrid halide perovskite-based materials. In-situ time-resolved grazing incidence wide angle x-ray scattering (GIWAXS) measurements performed during spin-coating reveal that organic gelators beneficially influence the nucleation and growth of the perovskite precursor phase. This can be exploited for the fabrication of planar n-i-p heterojunction devices with MAPbI3 (MA = CH3NH3 +) that display a performance that not only is enhanced by ~25% compared to solar cells where the active layer was produced without the use of a gelator but that also feature a higher stability to moisture and a reduced hysteresis. Most importantly, the presented approach is straight-forward and simple, and it provides a general method to render the film-formation of hybrid perovskites more reliable and robust, analogous to the control that is afforded by these additives in the processing of commodity ‘plastics’

    Conjugated polyelectrolyte hole transport layer for inverted-type perovskite solar cells

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    Organic-inorganic hybrid perovskite materials offer the potential for realization of low-cost and flexible next-generation solar cells fabricated by low-temperature solution processing. Although efficiencies of perovskite solar cells have dramatically improved up to 19% within the past 5 years, there is still considerable room for further improvement in device efficiency and stability through development of novel materials and device architectures. Here we demonstrate that inverted-type perovskite solar cells with pH-neutral and low-temperature solution-processable conjugated polyelectrolyte as the hole transport layer (instead of acidic PEDOT:PSS) exhibit a device efficiency of over 12% and improved device stability in air. As an alternative to PEDOT: PSS, this work is the first report on the use of an organic hole transport material that enables the formation of uniform perovskite films with complete surface coverage and the demonstration of efficient, stable perovskite/fullerene planar heterojunction solar cellsopen4

    Tetrathienoanthracene and Tetrathienylbenzene Derivatives as Hole-Transporting Materials for Perovskite Solar Cell

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    This is the peer reviewed version of the following article: Rojas, D. E. M., Cho, K. T., Zhang, Y., Urbani, M., Tabet, N., de la Torre, G., ... & Torres, T. (2018). Tetrathienoanthracene and Tetrathienylbenzene Derivatives as Hole‐Transporting Materials for Perovskite Solar Cell. Advanced Energy Materials, 8(25), 1800681, which has been published in final form at https://doi.org/10.1002/aenm.201800681. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThe synthesis and characterization of two related families of star-shaped thiophene-containing hole-transporting materials (HTMs) based on fused tetrathienoanthracene and nonfused tetrathienylbenzene cores are reported. All of them are endowed with four terminal (4,4′-dimethoxy)diphenylamino groups that are either linked directly to the core or showed a different type of bridges (i.e., thiophene-phenyl or phenyl rings). The novel HTMs are tested in mixed-ion perovskite (Cs0.1FA0.74MA0.13PbI2.48Br0.39) solar cells, and power conversion efficiencies of up to 18.8% are measured under 1 sun irradiation, comparable with the efficiency obtained for the reference cell using 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamine)-9,9′-spirobifluorene as an HTMThe authors are grateful for the financial support of the MINECO, Spain (CTQ2014‐52869‐P and CTQ2017‐85393‐P), the Comunidad de Madrid (FOTOCARBON, S2013/MIT‐2841). D.A.M. Rojas thanks the National Council on Science and Technology (CONACYT), No. 239120. M.U. thanks Cost Action (COST‐STSM‐MP1307) within the EU Framework Programme Horizon 2020. Nazeeruddin acknowledge SNSF NRP 70 project; number: 407040_154056, and CTI 15864.2 PFNM‐NM, Solaronix, Aubonne, Switzerland. The authors thank Borun New Material Technology for providing high quality spiro‐OMeTA

    Perovskite solar cells for roll-to-roll fabrication

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    Perovskite solar cell (PSCs) is considered as the game changer in emerging photovoltaics technology. The highest certified efficiency is 22% with high temperature processed (∼500 °C) TiO2 based electron transport layer (ETL). High temperature process is a rudimentary hindrance towards roll-to-roll processing of PSCs on flexible substrates. Low temperature solution process (<150 °C) ZnO based ETL is one of the most promising candidate for large scale roll-to-roll fabrication of cells as it has nearly identical electron affinity (4.2 eV) of TiO2. The mixed organic perovskite (MA0.6FA0.4PbI3) devices with Al doped ZnO (AZO) ETL demonstrate average cell efficiency over 16%, which is the highest ever reported efficiency for this device configuration. The energy level alignment and related interfacial charge transport dynamics at the interface of ZnO and perovskite films and the adjacent charge transport layers are investigated. Significantly improved device stability, hysteresis free device photocurrent have been observed in MA0.6FA0.4PbI3 cells. A systematic electrochemical impedance spectroscopy, frequency dependent capacitance spectra, surface morphology and topography characterization have been conducted to understand the role of interfacial electronic properties between perovskite and neighbouring layers in perovskite device. A standardized degradation study, interfacial electronic property and capacitive spectra analysis of aged device, have been measured to understand the enhanced device stability in mixed MA0.6FA0.4PbI3 cells. Slow perovskite material decomposition rate and augmented device lifetime with AZO based devices have been found to be correlated with the more hydrophobic and acidic nature of AZO surface compared to pristine ZnO film

    Coexpression and interaction of CXCL10 and CD26 in mesenchymal cells by synergising inflammatory cytokines: CXCL8 and CXCL10 are discriminative markers for autoimmune arthropathies

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    Leukocyte infiltration during acute and chronic inflammation is regulated by exogenous and endogenous factors, including cytokines, chemokines and proteases. Stimulation of fibroblasts and human microvascular endothelial cells with the inflammatory cytokines interleukin-1β (IL-1β) or tumour necrosis factor alpha (TNF-α) combined with either interferon-α (IFN-α), IFN-β or IFN-γ resulted in a synergistic induction of the CXC chemokine CXCL10, but not of the neutrophil chemoattractant CXCL8. In contrast, simultaneous stimulation with different IFN types did not result in a synergistic CXCL10 protein induction. Purification of natural CXCL10 from the conditioned medium of fibroblasts led to the isolation of CD26/dipeptidyl peptidase IV-processed CXCL10 missing two NH(2)-terminal residues. In contrast to intact CXCL10, NH(2)-terminally truncated CXCL10(3–77) did not induce extracellular signal-regulated kinase 1/2 or Akt/protein kinase B phosphorylation in CXC chemokine receptor 3-transfected cells. Together with the expression of CXCL10, the expression of membrane-bound CD26/dipeptidyl peptidase IV was also upregulated in fibroblasts by IFN-γ, by IFN-γ plus IL-1β or by IFN-γ plus TNF-α. This provides a negative feedback for CXCL10-dependent chemotaxis of activated T cells and natural killer cells. Since TNF-α and IL-1β are implicated in arthritis, synovial concentrations of CXCL8 and CXCL10 were compared in patients suffering from crystal arthritis, ankylosing spondylitis, psoriatic arthritis and rheumatoid arthritis. All three groups of autoimmune arthritis patients (ankylosing spondylitis, psoriatic arthritis and rheumatoid arthritis) had significantly increased synovial CXCL10 levels compared with crystal arthritis patients. In contrast, compared with crystal arthritis, only rheumatoid arthritis patients, and not ankylosing spondylitis or psoriatic arthritis patients, had significantly higher synovial CXCL8 concentrations. Synovial concentrations of the neutrophil chemoattractant CXCL8 may therefore be useful to discriminate between autoimmune arthritis types

    Citrullination of CXCL8 by peptidylarginine deiminase alters receptor usage, prevents proteolysis, and dampens tissue inflammation

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    Biological functions of proteins are influenced by posttranslational modifications such as on/off switching by phosphorylation and modulation by glycosylation. Proteolytic processing regulates cytokine and chemokine activities. In this study, we report that natural posttranslational citrullination or deimination alters the biological activities of the neutrophil chemoattractant and angiogenic cytokine CXCL8/interleukin-8 (IL-8). Citrullination of arginine in position 5 was discovered on 14% of natural leukocyte-derived CXCL8(1–77), generating CXCL8(1–77)Cit5. Peptidylarginine deiminase (PAD) is known to citrullinate structural proteins, and it may initiate autoimmune diseases. PAD efficiently and site-specifically citrullinated CXCL5, CXCL8, CCL17, CCL26, but not IL-1β. In comparison with CXCL8(1–77), CXCL8(1–77)Cit5 had reduced affinity for glycosaminoglycans and induced less CXCR2-dependent calcium signaling and extracellular signal-regulated kinase 1/2 phosphorylation. In contrast to CXCL8(1–77), CXCL8(1–77)Cit5 was resistant to thrombin- or plasmin-dependent potentiation into CXCL8(6–77). Upon intraperitoneal injection, CXCL8(6–77) was a more potent inducer of neutrophil extravasation compared with CXCL8(1–77). Despite its retained chemotactic activity in vitro, CXCL8(1–77)Cit5 was unable to attract neutrophils to the peritoneum. Finally, in the rabbit cornea angiogenesis assay, the equally potent CXCL8(1–77) and CXCL8(1–77)Cit5 were less efficient angiogenic molecules than CXCL8(6–77). This study shows that PAD citrullinates the chemokine CXCL8, and thus may dampen neutrophil extravasation during acute or chronic inflammation
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