Ethyl-, vinyl- and ethynylcyanoborates: Room temperature borate ionic liquids with saturated and unsaturated hydrocarbon chains

Ethyl-, vinyl- and ethynyltricyano and dicyanofluoroborates were prepared on gram scale from commercially available potassium trifluoroborates and trimethylsilylcyanide. Salt metathesis resulted in the corresponding EMIm-salts that are hydrophobic room-temperature ionic...

Stiff-Elongated Balance of PLA-Based Polymer Blends

In this study, polymer blends with a mechanical property balance based on poly(lactic acid) (PLA), stiff polymer, and elongated polymer were developed. First, the binary blends PLA-elongated polymer [ethyl vinyl acetate (EVA) or polyethylene], or PLA-stiff polymer [polystyrene or poly(styrene-co-methyl methacrylate) (SMMA)] blends were studied using dynamic mechanic analysis (DMA) and analyzed using Minitab statistical software to determine the factors influencing the elongation or stiffness of the blends. Then, ternary blends such as elongation-poly(lactic acid)-stiff, were made from the binary blends that presented optimal performance. In addition, three blends [EVA–PLA–SMMA (EPS)] were elaborated by studying the mixing time (5, 15, and 15 min) and the added time of the SMMA (0, 0, and 10 min). Specifically, the mixing time for EPS 1, EPS 2, and EPS 3 is 5 min, 15 min, and 15 min (first EVA + PLA for 10 min, plus 5 min PLA-EVA and SMMA), respectively. Mechanical, thermal, rheological, and morphological properties of the blends were studied. According to DMA, the results show an increase in elongation at break (εb) and do not decrease the elastic module of poly(lactic acid). Nevertheless, EPS 3 excels in all properties, with an εb of 67% and modulus of elasticity similar to PLA. SMMA has a significant role as a compatibilizing agent and improves PLA processability.

Hydrometallurgical Treatment for the Extraction and Separation of Indium and Gallium from End-of-Life CIGS Photovoltaic Panels

This study presents experimental results for the development of a process for the recovery of indium and gallium from EoL CIGS (CuGa1−xInxSe2) panels. The process consists of a thermal treatment of the panels, followed by a hydrometallurgical treatment, where quantitative leaching of In, Ga, Mo, Cu and Zn is achieved. The elements are subsequently separated and recovered from the leachate by solvent extraction. For the development of the process, samples of EoL CIGS PV panels were used, which contained a thin film of Mo (metal base electrode), sputtered on the supporting soda-lime glass and covered by the thin film containing In, Ga, Cu and Se (1 μm). These films were detected by SEM-EDS in polished sections. The thermal treatment at 550 °C for 15 min, in excess of air, led to the successful disintegration of ethyl vinyl acetate (EVA) and delamination of the thin film-coated glass from the front protective glass. The glass fragments coated by the thin film contained the following: Se: 0.03–0.05%; In: 0.02%; Cu: 0.05%; Ga: 0.004–0.006%; and Mo: 0.04%. Following thermal treatment, thin film-coated glass fragments of about 1.5 cm × 1.5 cm were used in acid leaching experiments using HNO3, HCl and H2SO4. Quantitative leaching of Cu, Ga, In, Mo, Zn and Cu was achieved by HNO3 at ambient temperature. The effects of pulp density and acid concentration on the efficiency of metal leaching were investigated. Part of Se volatilized during the thermal treatment, whereas the rest was insoluble and separated from the solution by filtration. Finally, the separation of the elements was achieved via solvent extraction by D2EHPA.

Efficiency improvement of solar cells by CaAlSiN3:Eu2+ and Y2O3:Eu3+ phosphors

CaAlSiN3:Eu2+ (CASN) and Y2O3:Eu3+ (YO) phosphors are mixed into ethyl vinyl-acetate (EVA) to form luminescence down-shifting (LDS) films which are used to improve crystalline silicon solar cells by converting the photons with the wavelength from 200 nm to 500 nm into red light. Experimental results show that the conversion efficiency of the solar cells is enhanced from 19.61% to 20.00%. The improvement is better than that with only CASN phosphors in EVA films. The reason is the high quantum yield of YO phosphors in the wavelength range 250 nm-350 nm, which offsets the poorer performance of CASN phosphors in this wavelength range.

Multi-Wire Interconnection of Busbarless Solar Cells with Embedded Electrode Sheet

The module technology proposed in this paper is used to fabricate a wire embedded ethyl vinyl acetate (EVA) sheet module by applying a cell/module integrated process in which the cell and wire are bonded during the lamination process. A wire-embedded EVA sheet module was fabricated using a busbarless cell and SnBiAg wire. As a result of the module characteristics corresponding to the lamination process temperature, the highest efficiency of 19.55% was observed at 170 °C. The lowest contact resistivity between the wire and the finger electrode was shown under a temperature condition of 170 °C, which was confirmed to increase the efficiency owing to an improvement of the fill factor with an excellent electrical contact.

SiO2-Ag Composite as a Highly Virucidal Material: A Roadmap that Rapidly Eliminates SARS-CoV-2

COVID-19, as the cause of a global pandemic, has resulted in lockdowns all over the world since early 2020. Both theoretical and experimental efforts are being made to find an effective treatment to suppress the virus, constituting the forefront of current global safety concerns and a significant burden on global economies. The development of innovative materials able to prevent the transmission, spread, and entry of COVID-19 pathogens into the human body is currently in the spotlight. The synthesis of these materials is, therefore, gaining momentum, as methods providing nontoxic and environmentally friendly procedures are in high demand. Here, a highly virucidal material constructed from SiO2-Ag composite immobilized in a polymeric matrix (ethyl vinyl acetate) is presented. The experimental results indicated that the as-fabricated samples exhibited high antibacterial activity towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as well as towards SARS-CoV-2. Based on the present results and radical scavenger experiments, we propose a possible mechanism to explain the enhancement of the biocidal activity. In the presence of O2 and H2O, the plasmon-assisted surface mechanism is the major reaction channel generating reactive oxygen species (ROS). We believe that the present strategy based on the plasmonic effect would be a significant contribution to the design and preparation of efficient biocidal materials. This fundamental research is a precedent for the design and application of adequate technology to the next-generation of antiviral surfaces to combat SARS-CoV-2.