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Among various kinds of photothermal conversion materials, polypyrrole (PPy) has attracted ever‐increasing attention because of its good biocompatibility and excellent near‐infrared light response property. In this research, the core‐shell nanoparticles with magnetic Fe3O4 as the core and mesoporous silica (MSN) as the shell were prepared, the resulted Fe3O4@MSN nanoparticles were then surface coated with a layer of PPy and further modified with polyvinylpyrrolidone (PVP) to gain colloidal stability. The Fe2+ in Fe3O4 can catalyze the decomposition of H2O2 in tumor cells to produce cytotoxic hydroxyl radicals, thus realizing the tumor chemodynamic therapy. Meanwhile, the MSN layer gives the nanoparticles a higher drug loading capacity of chemotherapeutics (doxorubicin, DOX). Therefore, the prepared Fe3O4@MSN@PPy‐PVP nanoparticles not only have good biocompatibility, magnetism and colloidal stability but also can realize the combined tumor photothermal, chemo, and chemodynamic therapy. This study demonstrates the rational design of multifunctional nanoplatforms for biomedical applications. [ABSTRACT FROM AUTHOR]

Herein, a series of Eu2+&Mn2+substituted fluorophosphates Ca6Gd2Na2(PO4)6F2 phosphor with apatite structure have been synthesized and investigated by the powder X-ray diffraction, photoluminescence spectra, fluorescence decay curves, thermal quenching, and chromaticity properties. Particularly, both Eu2+ and Mn2+ emissions at the two different lattice sites 4 f and 6 h in Ca6Gd2Na2(PO4)6F2 matrix have been identified and discussed. The dual energy transfer of Eu2+→Mn2+ and Gd3+→Mn2+ in Ca6Gd2Na2(PO4)6F2:Eu2+,Mn2+ samples have been validated and confirmed by the photoluminescence spectra. The dependence of color-tunable on the activator concentration of Mn2+ was investigated to realize white light emission. By varying the doping concentration of the Mn2+ ion, a series of tunable colors including pure white light and candle light are obtained under the excitation of 350 nm. Moreover, the fluorescence decay curves have been fitted and analyzed using the Inokuti-Hirayama theoretical model to estimate the Eu-Mn interaction mechanism. We also investigated temperature-dependent photoluminescence quenching characteristics according to the Arrhenius equation. Preliminary studies on the properties of the phosphor indicated that the obtained phosphors might have potential application as a single-component white-emitting phosphor for UV-based white LEDs. [ABSTRACT FROM AUTHOR]

Thermal quenching has always been one of the most difficult issues in creating high-quality phosphor conversion light-emitting diodes (pc-LED), and a family of strategies are urgently needed to improve the luminescence performance of phosphors at high temperatures. In this contribution, a novel B'-site substitution CaLaMgSb x Ta 1- x O 6 :Bi 3+ phosphor was constructed using an ion substitution strategy in the matrix with a green activator Bi 3+ and a novel double perovskite material. When Sb 5+ replaces Ta 5+ , a surprising increase in luminescence intensity occurs and the thermal quenching properties are greatly improved. The shift of the Raman characteristic peak to a smaller wavenumber and the reduction of the Bi-O bond length confirm that the crystal field environment around Bi 3+ changes, which has a substantial effect on the crystal field splitting and nepheline effect of Bi 3+ ions, affecting the crystal field splitting energy ( D q ). This results in a corresponding increase of the band gap and the thermal quenching activation energy (Δ E ) of the activator Bi 3+ . From the perspective of D q , the intrinsic relationships among the activator ion band gap, bond length, and Raman characteristic peak changes were analyzed, and a mechanism for regulating luminescence thermal quenching properties was constructed, which provides an effective strategy for improving the promising new materials such as double perovskite.

The combination of reactive oxygen species (ROS)-induced chemodynamic therapy (CDT) and photothermal therapy (PTT) holds a promising application prospect for their superb anticancer efficiency. Herein, we created a novel Fe 3 O 4 @polydopamine (PDA)@bovine serum albumin (BSA)-Bi 2 S 3 composite as a theranostic agent, by chemically linking the Fe 3 O 4 @PDA with BSA-Bi 2 S 3 via the amidation between the carboxyl groups of BSA and the amino groups of PDA. In this formulation, the Fe 3 O 4 NPs could not only work as a mimetic peroxidase to trigger Fenton reactions of the innate H 2 O 2 in the tumor and generate highly cytotoxic hydroxyl radicals (•OH) to induce tumor apoptosis but also serve as the magnetic resonance imaging (MRI) contrast agent to afford the precise cancer diagnosis. Meanwhile, the PDA could prevent the oxidization of Fe 3 O 4 , thus supporting the long-term Fenton reactions and the tumor apoptosis in the tumor. The Bi 2 S 3 component exhibits excellent photothermal transducing performance and computed tomography (CT) imaging capacity. In addition, the PDA and Bi 2 S 3 endow the Fe 3 O 4 @PDA@BSA-Bi 2 S 3 composite with an excellent photothermal transforming ability which could lead to tumor hyperthermia. All of these merits play the synergism with the tumor microenvironment and qualify the Fe 3 O 4 @PDA@BSA-Bi 2 S 3 NPs for a competent agent in the MRI/CT-monitored enhanced PTT/CDT synergistic therapy. Findings in this research will evoke new interests in future cancer therapeutic strategies based on biocompatible nanomaterials.

In this study, we synthesized and characterized a series of Eu(2+) and Mn(2+)-coactivated fluoro-apatite-structure Ca6Y2Na2(PO4)6F2 phosphors, which can provide high-quality standard white emission from a single-phase host. The powder X-ray diffraction, photoluminescence spectra, fluorescence decay curves, chromaticity coordinates, and correlated color temperature of the obtained phosphors were measured and are discussed in detail. Energy transfer from the Eu(2+) to the Mn(2+) ions was demonstrated by the overlap between the emission spectrum of the Eu(2+) ions and the excitation spectrum of the Mn(2+) ions, and the systematic relative decline and growth of the emission bands of Eu(2+) and Mn(2+), respectively. A possible energy transfer mechanism was proposed based on the experimental results and analysis. It was discovered that the emission colors of the phosphor varied from blue through white and eventually to yellow by properly tuning the doping content of Mn(2+) with a fixed Eu(2+) content through the principle of energy transfer. The developed phosphors can be efficiently excited in the UV region and exhibit white-light emission, making them attractive as white-emitting conversion phosphors for UV-based white light emitting diodes.