Carbon-based materials for stable, cheaper and large-scale processable perovskite solar cells

Replacing gold and boosting stability: carbon as Holy Grail for perovskite solar cells

Structure–Performance Correlation of Nanocellulose‐Based Polymer Electrolytes for Efficient Quasi‐solid DSSCs

Nanoscale microfibrillated cellulose (NMFC) was introduced into a light-cured polymeric matrix to result in a green, cheap, and highly efficient quasi-solid electrolyte for the next-generation of bio-based dye-sensitized solar cells. The effect of NMFC on the photovoltaic parameters and performance of the resulting photo-electrochemical cells was thoroughly investigated, and a noticeable increase in both the photocurrent (due to optical phenomena) and the photovoltage (through a shielding effect on the recombination reactions) was demonstrated. Upon thorough optimization of the amount of NMFC introduced into the polymeric network, sunlight conversion efficiencies as high as 7.03 and 8.25 % were achieved at simulated light intensities of 1.0 and 0.4 sun, respectively. Furthermore and outstandingly, the addition of NMFC positively affected the long-term stability of the device, which was able to retain >95 % of its initial efficiency after 500 h of extreme aging condition

Cobalt-Based Electrolytes for Dye-Sensitized Solar Cells: Recent Advances towards Stable Devices

Redox mediators based on cobalt complexes allowed dye-sensitized solar cells (DSCs) to achieve efficiencies exceeding 14%, thus challenging the emerging class of perovskite solar cells. Unfortunately, cobalt-based electrolytes demonstrate much lower long-term stability trends if compared to the traditional iodide/triiodide redox couple. In view of the large-scale commercialization of cobalt-based DSCs, the scientific community has recently proposed various approaches and materials to increase the stability of these devices, which comprise gelling agents, crosslinked polymeric matrices and mixtures of solvents (including water). This review summarizes the most significant advances recently focused towards this direction, also suggesting some intriguing way to fabricate third-generation cobalt-based photoelectrochemical devices stable over time

Discriminating between negative cooperativity and ligand binding to independent sites using pre-equilibrium properties of binding curves

Negative cooperativity is a phenomenon in which the binding of a first ligand or substrate molecule decreases the rate of subsequent binding. This definition is not exclusive to ligand-receptor binding, it holds whenever two or more molecules undergo two successive binding events. Negative cooperativity turns the binding curve more graded and cannot be distinguished from two independent and different binding events based on equilibrium measurements only. The need of kinetic data for this purpose was already reported. Here, we study the binding response as a function of the amount of ligand, at different times, from very early times since ligand is added and until equilibrium is reached. Over those binding curves measured at different times, we compute the dynamic range: The fold change required in input to elicit a change from 10 to 90% of maximum output, finding that it evolves in time differently and controlled by different parameters in the two situations that are identical in equilibrium. Deciphering which is the microscopic model that leads to a given binding curve adds understanding on the molecular mechanisms at play, and thus, is a valuable tool. The methods developed in this article were tested both with simulated and experimental data, showing to be robust to noise and experimental constraints.Fil: Sevlever, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Di Bella, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Ventura, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

PEO/LAGP hybrid solid polymer electrolytes for ambient temperature lithium batteries by solvent-free, “one pot” preparation

Here, we report hybrid solid polymer electrolytes (HSPE) obtained by rapid, truly solvent-free, thus scalable preparation process. HSPE composition is very simple: a LiTFSI added poly(ethylene oxide) (PEO) polymer matrix encompassing NASICON-type Li1.5Al0.5Ge1.5(PO4)3 (LAGP) super Li+ ion conducting ceramic. Homogeneous, self-standing, mechanically robust solid electrolyte films are obtained by simply mixing in “one pot” and hot pressing the solid mixture of dry powders at moderate temperature. Noteworthy, unlike several other super ionic conductors used for composite electrolytes, LAGP is relatively stable in air atmosphere and can be processed in a dry-room, which is more favorable, cheap and scalable than Ar-filled dry glove box for industrial fabrication of safe lithium batteries. The proper, homogeneous mixing of LAGP powder, PEO and LiTFSI leads to HSPE with interesting electrochemical behavior in lab-scale lithium cells, especially under high current regimes, and even at ambient temperature. HSPE-based cells outperform the PEO-LiTFSI-based counterpart, in terms of specific capacity output (about 70% of the theoretical value retained at very high 2C rate), limited fading and excellent Coulombic efficiency (>99.5%) even at low rate. Interfacial stability issues remain to be solved, chiefly linked to the reactivity of LAGP in contact with lithium metal, but results here proposed represent a step further toward truly all-solid-state batteries conceived for high energy/power technologies, assuring safety and performance in a wide range of operating conditions

Estimation of the radioactive source dispersion from Fukushima nuclear power plant accident

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Ground gamma-ray survey of the Solforata gas discharge area, Alban Hills-Italy: A comparison between field and laboratory measurements

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Performance of real evapotranspiration products and water yield estimations in Uruguay

Real evapotranspiration (ETR) is a key variable in socio-ecological systems since it is related to the food supply, climate regulation, among others. Also, ETR strongly determines the water yield (WY) at the catchment level (water available for consumption or irrigation). In that sense, quantifying ETR and WY fluctuations linked to various human pressures is essential for comprehensive water planning. In the last decades, remote sensing ETR estimations have become increasingly performed worldwide for hydrological monitoring. In Uruguay, there are several attempts to quantify the ETR through different approaches. However, assessments related to the performance of the estimates of different sources/products, particularly from remote sensing, are still lacking. The main objectives of this article were: a) to evaluate the performance of different spatial explicit approaches to estimate real ETR and b) to estimate and analyse the variability in water yield derived from the different ETR sources/products for three climatically contrasting years. To achieve this, we used four remote sensing ETR products (PMLv2, MOD16A2, Jackson et al. 1977 and Di Bella et al. 2000), with different spatial and temporal resolutions (from 500 to 1000-m and 8 to 16-d), and two water balance models at two scales, national (INIA-GRAS) and micro-watershed level (Silveira et al. 2016). Our results suggest that MODIS and PMLv2 remote sensing products demonstrated better performances. Both products have high spatial (500-m) and temporal (8-d) resolution, captured seasonal differences between land-covers and showed positive and high correlations with the annual precipitation and productivity. The differences found between products have direct implications on the WY estimates, not only in the quantity but also in its spatial pattern. Future studies should explore MODIS and PML ETR estimations for understanding hydrological and ecological processes, global climate change research, agricultural drought detection and mitigation, and water resource management.Agencia Nacional de Investigación e Innovació