Yan Gao

In this paper, we describe the formation and luminescence of a new garnet phosphor for light emitting diode (LED) based lighting, Lu2CaMg2(Si,Ge)3O12:Ce3+. The regions for garnet phase formation are initially described with respect to larger rare earth substitution and show reasonable correlation to previous crystal chemistry studies for the garnet parent structure. While the pure silicate phosphor also has apatite second phases, a significant amount of Ce3+ enters the garnet phase, giving Ce3+ luminescence that is significantly redder when compared to typical Al3+ garnet phosphors with quantum efficiencies comparable to commercial Ce3+ garnet phosphors. Potential reasons for the emission red shift and the high quantum efficiency are discussed. Finally, the performance of these new phosphors is tested within LED based lamps. Lamps using these phosphors can reach color temperatures required for general illumination lighting and also have comparable phosphor conversion efficiencies when compared to lamps using typical garnet phosphors.

Biological systems possess inherent molecular recognition and self-assembly capabilities and are attractive templates for constructing complex material structures with molecular precision. Here we report the assembly of various nanoachitectures including nanoparticle arrays, hetero-nanoparticle architectures, and nanowires utilizing highly engineered M13 bacteriophage as templates. The genome of M13 phage can be rationally engineered to produce viral particles with distinct substrate-specific peptides expressed on the filamentous capsid and the ends, providing a generic template for programmable assembly of complex nanostructures. Phage clones with gold-binding motifs on the capsid and streptavidin-binding motifs at one end are created and used to assemble Au and CdSe nanocrytals into ordered one-dimensional arrays and more complex geometries. Initial studies show such nanoparticle arrays can further function as templates to nucleate highly conductive nanowires that are important for addressing/interconnecting individual nanostructures.

We have determined the structures of two phases of unsolvated Mg(BH(4))(2), a material of interest for hydrogen storage. One or both phases can be obtained depending on the synthesis conditions. The first, a hexagonal phase with space group P6(1), is stable below 453 K. Upon heating above that temperature it transforms to an orthorhombic phase, with space group Fddd, stable to 613 K at which point it decomposes with hydrogen release. Both phases consist of complex networks of corner-sharing tetrahedra consisting of a central Mg atom and four BH(4) units. The high-temperature orthorhombic phase has a strong antisite disorder in the a lattice direction, which can be understood on the basis of atomic structure.

Nanoplastic uptake in plants has drawn increasing attention for its potential toxicity to organisms at higher trophic levels. However, the mechanisms remain ambiguous due to the lack of quantitative methods for nanoplastic uptake in plants. Herein, a novel procedure incorporating alkaline digestion, cellulose precipitation, and ultrasonic leaching, followed by pyrolysis gas chromatography–mass spectrometry (Py-GC/MS) analysis, was developed to quantify nanoplastic uptake in plants with cucumber (Cucumis sativus) as the model species. Recoveries of 81.6%–97.2% were obtained for polystyrene (PS) and poly(methyl methacrylate) (PMMA) nanoplastics at spiking levels of 34.5–61.5 μg/g in quality control samples. Detection limits of 2.31–4.15 μg/g for PS and 3.87–8.20 μg/g for PMMA nanoplastics were achieved. After exposure to 50 mg/L of 100 nm PS nanoplastics for 7 and 14 days, 0–6893 μg/g nanoplastics were detected in various dried cucumber tissues using the developed method with their presence identified by scanning electron microscopy (SEM), suggesting nanoplastic uptake, translocation, and accumulation in plants. Comparative experiments with inductively coupled plasma mass spectrometry (ICP-MS) using palladium-labeled nanoplastics further confirmed the promising application of our method in quantifying nanoplastic uptake in plants. Consequently, the proposed method provides new possibilities for screening nanoplastics in plants.