Enhancement of dye sensitized solar cell efficiency via incorporation of upconverting phosphor nanoparticles as spectral converters

Upconverting NaYF₄:Yb³⁺,Er³⁺/NaYF₄ core‐shell (CS) nanoparticles (NPs) were synthesized by thermal decomposition of lanthanide trifluoroacetate precursors and mixed with TiO₂ NPs to fabricate dye‐sensitized solar cells (DSSCs). The CS geometry effectively prevents the capture of electrons because of the surface states and improves photo‐emission. The as‐synthesized CS NPs show upconversion (UC) luminescence, converting near infrared (NIR) light into visible light (450–700 nm), making the photon absorption by the ruthenium‐based dyes (which have little or no absorption in the NIR region) possible. The champion DSSCs fabricated using CS UC NPs (average size = 25 nm) show enhancements of ~12.5% (sensitized with black/N749 dye) and of ~5.5% (sensitized with N719 dye) in overall power conversion efficiency under AM 1.5G illumination. This variation in the enhancement of the DSSC efficiencies for black and N719 dyes is attributed to the difference in the extinction coefficient and the absorption wavelength range of dyes. Incident photon‐to‐current conversion efficiency measurements also evidently showed the photocurrent enhancement in the NIR region of the spectrum because of the UC effect. The results prove that the augmentation in efficiency is primarily due to NIR to visible spectrum modification by the fluorescent UC NPs. Copyright © 2015 John Wiley & Sons, Ltd.     

Aflatoxins: Biosynthesis,Occurrence, Toxicity,and Remedies

Food contagion with aflatoxins is the modern concern and has received a great awareness during the last few decades. The intermittent incidence of these toxins in agricultural commodities has negative role on the economy of the affected regions where harvest and postharvest techniques for the prevention of mold growth, are seldom practiced. Aflatoxins are difuranocoumarin derivatives produced by a polyketide pathway by the fungus Aspergillus flavus and Aspergillus parasiticus via polyketide pathway which are highly hepatotoxic, hepatocarcinogenic, teratogenic, and mutagenic in nature and contaminate a wide variety of important agricultural commodities before, during, and after harvest in various environmental conditions. The production of aflatoxins in innate substrates depends upon the various factors, that is, type of substrate, fungal species, moisture contents of the substrate, minerals, humidity, temperature, and physical damage of the kernels. These toxins cause several ailments such as cancer, hepatitis, mutation abnormalities, and reproduction disorders. Minimization and inactivation of aflatoxins contaminants through proper crop management at farm level and with physical, chemical, and biological techniques are the limelight of the article.     

Structural variation in soft segment of waterborne polyurethane acrylate nanoemulsions

High solid content waterborne polyurethane acrylate (WPUA) nanoemulsions are prepared as textile finishes. Two structurally different soft segments, that is, polyether and polyester are used with isophorone diisocyanate, 2‐hydroxyethyl methacrylate, and butyl acrylate. Structural variations are investigated in features of nanoemulsions and their coatings. Physical properties of nanoemulsions, such as average particle size, stability, solid content, and viscosity, are investigated. Nanoemulsions with high solid content, that is, 40–47% are produced without any internal emulsifier. Average nanoparticle size, that is, <100 nm is confirmed by dynamic light scattering and atomic force microscopy (AFM). Fourier transform infrared spectroscopy proved synthesis of proposed WPUA products. Synergistic effect of polyurethane and acrylate is observed in chemical and water resistance of WPUA. Differential scanning calorimetry (DSC) and thermogravimetric analysis indicate stable uniformly cross‐linked network of WPUA. Application of nanoemulsions on 100% cotton fabric shows a significant improvement in tear strength, which is more pronounced for polyester‐based WPUA. Scanning electron microscope images of treated fabric samples show good adhesion of nanoemulsions on cotton surface. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41706.     

IoHT-based deep learning controlled robot vehicle for paralyzed patients of smart cities

The Journal of Supercomputing - Paralysis caused by physical trauma is a common disease today, with approximately 30% of paralysis caused by this trauma. The disease in question both physically...     

Performance Improvement of Glass Fiber/Epoxy Composites Upon Integrating with N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane Functionalized Graphene Oxide

Journal of Inorganic and Organometallic Polymers and Materials - Surface tuned GO sheets are considered the opportune pothunter for the reinforcement of conventional glass fiber reinforced...     

Retraction Note to: Effect of Urea on the Morphology of Fe3O4 Magnetic Nanoparticles and their Application in Potentiometric Urea Biosensors

Silicon - The Editor-in-Chief has retracted this article [1] because Figure 4 and Figure 5 appear to show cobalt oxide nanoparticles and not iron oxide nanoparticles as stated in the article. The...     

Metallocorroles as Electrocatalysts for the Oxygen Reduction Reaction (ORR)

The oxygen reduction reaction (ORR) is the most important reaction in life processes and in energy transformation, such as fuel cells. Normally, the ORR in a fuel cell is very slow and a cathode ORR catalyst is needed to reach a practical usable level. Pt-based materials are the most effective catalysts, but they are too expensive to make fuel cells commercially viable and hence extensive research has focused on developing alternative catalysts. First row transition metallocorroles are potent catalysts for many reactions, and they may eventually be used as true alternatives to the precious metals currently used. Regarding ORR, brominated cobalt corrole has been shown to operate almost as well as an industry standard platinum-based catalyst. In this review, we would like to summarize the progress that has been made in this field.