Eu(III)-doped Y(2)O(3) nanocrystals are prepared by microwave synthetic methods as spherical 6.4 ± 1.5 nm nanocrystals with a cubic crystal structure. The surface of the nanocrystal is passivated by acetylacetonate (acac) and HDA on the Y exposed facet of the nanocrystal. The presence of acac on the nanocrystal surface gives rise to a strong S(0) → S(1) (π → π*, acac) and acac → Ln(3+) ligand to metal charge transfer (LMCT) transitions at 270 and 370 nm, respectively, in the Eu:Y(2)O(3) nanocrystal. Excitation into the S(0) → S(1) (π → π*) or acac → Ln(3+) LMCT transition leads to the production of white light emission arising from efficient intramolecular energy transfer to the Y(2)O(3) oxygen vacancies and the Eu(III) Judd-Ofelt f-f transitions. The acac passivant is thermally stable below 400 °C, and its presence is evidenced by UV-vis absorption, FT-IR, and NMR measurements. The presence of the low-lying acac levels allows UV LED pumping of the solid phosphor, leading to high quantum efficiency (∼19%) when pumped at 370 nm, high-quality white light color rendering (CIE coordinates 0.33 and 0.35), a high scotopic-to-photopic ratio (S/P = 2.21), and thermal stability. In a LED lighting package luminosities of 100 lm W(-1) were obtained, which are competitive with current commercial lighting technology. The use of the passivant to funnel energy to the lanthanide emitter via a molecular antenna effect represents a new paradigm for designing phosphors for LED-pumped white light.

A century ago Ostwald described the "Rule of Stages" after deducing that crystal formation must occur through a series of intermediate crystallographic phases prior to formation of the final thermodynamically stable structure. Direct evidence of the Rule of Stages is lacking, and the theory has not been implemented to allow isolation of a selected structural phase. Here we report the role of Ostwald's Rule of Stages in the growth of CdSe quantum dots (QDs) from molecular precursors in the presence of hexadecylamine. It is observed that, by controlling the rate of growth through the reaction stoichiometry and therefore the probability of ion-packing errors in the growing QD, the initially formed zinc blende (ZB) critical nuclei representing the kinetic phase can be maintained at sizes >14 nm in diameter without phase transformation to the thermodynamic wurtzite (WZ) structure. An intermediate pseudo-ZB structure is observed to appear at intermediate reaction conditions, as predicted by Ostwald. The ZB and pseudo-ZB structures convert to the WZ lattice above a critical melting temperature. This study validates Ostwald's Rule of Stages and provides a phase diagram for growth of CdSe QDs exhibiting a specific crystallographic motif.

This paper describes the synthesis of Eu(III)doped ZnB 2 O 4 (B = Al(III) or Ga(III)) nanospinels with Eu(III) concentrations varying between 1% and 15.6%. The synthesis was achieved through a microwave (MW) synthetic methodology producing 3 nm particles by the thermal decomposition of zinc undecylenate (UND) and a metal 2,4pentanedionate (B(acac) 3 , B = Al 3+ or Ga 3+ ) in oleylamine (OAm). The nanospinels were then ligand exchanged with the β-diketonate, 2-thenoyltrifluoroacetone (tta). Using tta as a ligand on the surface of the particles resulted in soluble materials that could be embedded in lens mimics, such as poly(methyl methacrylate) (PMMA). Through a Dexter energy transfer mechanism, tta efficiently sensitized the Eu(III) doped within the nanospinels, resulting in red phosphors with intrinsic quantum efficiencies (QEs) and QEs in PMMA as high as 50% when excited in the UV. Optical measurements on the out of batch and tta-passivated nanospinels were done to obtain absorption, emission, and lifetime data. The structural properties of the nanospinels were evaluated by ICP-MS, pXRD, TEM, FT-IR, EXAFS, and XANES.

Perovskite‐like metal‐organic frameworks (MOFs) are hybrid materials of high interest for their potential in information storage technology, as Pb‐free substitutes for the widely used lead zirconate titanate (PZT) family of multiferroics. We report here a new, microwave‐assisted method of synthesis for perovskite‐like MOFs, which exploits the advantages of rapid and volumetric heating by microwaves in order to achieve synthesis within minutes, compared to days required by previously reported methods. The preliminary results demonstrate a broad control over the size and morphology of the products, by minor changes in the reaction conditions. An investigation of the effects of size and morphology on the magnetic and dielectric properties is presented here. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

Research over the past decade has identified several of the key limiting features of multidrug resistance (MDR) in cancer therapy applications, such as evolving glycoprotein receptors at the surface of the cell that limit therapeutic uptake, metabolic changes that lead to protection from multidrug resistant mediators which enhance degradation or efflux of therapeutics, and difficulty ensuring retention of intact and functional drugs once endocytosed. Nanoparticles have been demonstrated to be effective delivery vehicles for a plethora of therapeutic agents, and in the case of nucleic acid based agents, they provide protective advantages. Functionalizing cell penetrating peptides, also known as protein transduction domains, onto the surface of fluorescent quantum dots creates a labeled delivery package to investigate the nuances and difficulties of drug transport in MDR cancer cells for potential future clinical applications of diverse nanoparticle-based therapeutic delivery strategies. In this study, eight distinct cell penetrating peptides were used (CAAKA, HSV1-VP22, HIV-TAT, HIV-gp41, Ku-70, hCT(9-32), integrin-β3, and K-FGF) to examine the different cellular uptake profiles in cancer versus drug resistant melanoma (A375 & A375-R), mesothelioma (MSTO & MSTO-R), and glioma (rat 9L and 9L-R, and human U87 & LN18) cell lines. The results of this study demonstrate that cell penetrating peptide uptake varies with drug resistance status and cell type, likely due to changes in cell surface markers. This study provides insight into developing functional nanoplatform delivery systems in drug resistant cancer models.