Eu:YPO 4 •xH 2 O (x = 0.5−1) nanocrystals were synthesized by a liquid−solid−solution (LSS) solvothermal method and dispersed in chloroform. In order to sensitize the emission from the Eu 3+ ions, 2-thenoyltrifluoroacetone (HTTFA) was used to replace a significant fraction of the oleate capping ligand on the as-prepared Eu:YPO 4 •xH 2 O (x = 0.5−1) nanocrystals. During the ligand exchange, HTTFA reacts with oleate, forming oleic acid and 2-thenoyltrifluoroacetonate, TTFA. The negatively charged TTFA then displaces the neutral oleic acid ligand from the surface of the nanoparticles. The resulting surface-modified samples were less dispersible in chloroform than were the as-prepared, oleate-capped nanoparticles but were easily dispersed in pyridine, forming very clear mixtures. The resulting surface-modified nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), UV−vis absorption spectroscopy, photoluminescence (PL) spectroscopy, and time-resolved luminescence spectroscopy. XRD analysis indicates that the samples are crystalline with a hexagonal phase. The oleate-capped Eu:YPO 4 •xH 2 O (x = 0.5−1) nanocrystals have a zeolite structure with a porous surface. The morphology and quality of the nanoparticles remained unchanged upon ligand exchange. The FTIR spectrum of the surfacemodified (TTFA-sensitized) Eu:YPO 4 •xH 2 O (x = 0.5−1) nanocrystals shows signals for both 2-thenoyltrifluoroacetate and oleate. Using UV−vis absorbance and elemental analysis, it is estimated that approximately half of the native oleate capping ligands are replaced with TTFA. Colloidal dispersions in pyridine show characteristic emission of Eu 3+ 5 D 0 → 7 F J (J = 0−4) when excited at the TTFA absorbance band at 350 nm. Ligand excitation at 350 nm results in an enhancement of external quantum efficiency of Eu 3+ emission of up to 4700× relative to direct Eu 3+ excitation at 464 nm. The ability to sensitize emission from these nanocrystals greatly increases their potential for application in display and lighting fields.

Electron−phonon coupling controls nonradiative relaxation dynamics of the photoexcited electron−hole pair in semiconductor nanostructures. Here the optoelectronic properties for Al-and P-codoped silicon quantum dots (QDs) are calculated by combining time-dependent density matrix methodology and ab initio electronic structure methods. The energy-band landscape of the codoped Si QD is elucidated via time evolution of population density distributions in energy and in coordinate space. Multiple nonradiative relaxation pathways result in a specific charge-separated state, where a hole and an electron are localized on Al and P dopants, respectively. Analysis of the simulated nonradiative decay shows that high-energy photoexcitation relaxes to the band gap edge within 10 ps, forming the final charge-transfer state. We also simulate time-resolved emission spectra of the codoped Si QD that reveals optical and IR emissions below the optical band gap. These emission features are attributed to the intraband transitions introduced by doping.

Sesame (Sesamum indicum L.), of the Pedaliaceae family, is one of the first oil crops used in humans. It is widely grown and has a mellow flavor and high nutritional value, making it very popular in the diet. Sesame seeds are rich in protein and lipids and have many health benefits. A number of in vitro and in vivo studies and clinical trials have found sesame seeds to be rich in lignan-like active ingredients. They have antioxidant, cholesterol reduction, blood lipid regulation, liver and kidney protection, cardiovascular system protection, anti-inflammatory, anti-tumor, and other effects, which have great benefits to human health. In addition, the aqueous extract of sesame has been shown to be safe for animals. As an important medicinal and edible homologous food, sesame is used in various aspects of daily life such as food, feed, and cosmetics. The health food applications of sesame are increasing. This paper reviews the progress of research on the nutritional value, chemical composition, pharmacological effects, and processing uses of sesame to support the further development of more functionalities of sesame.

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High antistatic HDPE composites were firstly prepared by solution blending with polyaniline encapsulated graphene nanoplatelets nanocomposites.