Highly Sensitive Dual-Phase Nanoglass-Ceramics Self-Calibrated Optical Thermometer

A strategy to achieve high sensitivity of noncontact optical thermometer via the structure design of nanoglass-ceramic and the usage of Ln³⁺ (Ln = Eu, Tb, Dy) luminescence as reference signal and Cr³⁺ emission as temperature signal was provided. Specifically, the synthesized dual-phase glass-ceramics were evidenced to enable spatially confined doping of Ln³⁺ in the hexagonal GdF₃ nanocrystals and Cr³⁺ in the cubic Ga₂O₃ nanoparticles, being beneficial to suppressing detrimental energy transfer between Ln³⁺ and Cr³⁺ and thus significantly enhancing their luminescence. As a consequence, completely different temperature-sensitive luminescence of Ln³⁺4f → 4f transition and Cr³⁺ 3d → 3d transition in the present glass-ceramic resulted in obvious variation of Cr³⁺/Ln³⁺ fluorescence intensity ratio with temperature and strikingly high detecting temperature sensitivity of 15–22% per K. We believe that this preliminary study will provide an important advance in exploring other innovative optical thermometry

Full-Spectral Fine-Tuning Visible Emissions from Cation Hybrid Cs_1–<i>m</i>FA<i>_m</i>PbX₃ (X = Cl, Br, and I, 0 ≤ <i>m</i> ≤ 1) Quantum Dots

Full-color visible emissions are particularly crucial for applications in displays and lightings. In this work, we developed a facile room-temperature ligand-assisted supersaturated recrystallization synthesis of monodisperse, cubic structure Cs_1–<i>m</i>FA<i>_m</i>PbX₃ (X = Cl, Br, and I or their mixtures Cl/Br and Br/I, 0 ≤ <i>m</i> ≤ 1) hybrid perovskite quantum dots (QDs). Impressively, cation substitution of Cs⁺ by FA⁺ was beneficial in finely tuning the band gap and in exciton recombination kinetics, improving the structural stability, and raising the absolute quantum yields up to 85%. With further assistance of anion replacement, full-spectral visible emissions in the wavelength range of 450–750 nm; narrow full width at half-maxima, and a wide color gamut, encompassing 130% of National Television System Committee television color standard, were achieved. Finally, Cs_1–<i>m</i>FA<i>_m</i>PbX₃-polymer films retaining multicolor luminescence are prepared and a prototype white light-emitting diode device was constructed using green Cs_0.1FA_0.9PbBr₃ and red Cs_0.1FA_0.9Br_1.5I_1.5 QDs as color converters, certainly suggesting their potential applications in the optoelectronics field

EuF₃/Ga₂O₃ Dual-Phase Nanostructural Glass Ceramics with Eu²⁺/Cr³⁺ Dual-Activator Luminescence for Self-Calibrated Optical Thermometry

To circumvent the requirement of small energy gap between thermally coupled levels of lanthanide probes in optical thermometry, a strategy using dual-activator fluorescence intensity ratio as temperature signal in dual-phase nanostructural glass ceramics was reported. Specifically, oxyfluoride glass with specially designed composition of SiO₂–Al₂O₃–LiF–EuF₃–Ga₂O₃–Cr₂O₃ was fabricated, and subsequently glass crystallization was used to induce homogeneous precipitation of hexagonal EuF₃ and cubic Ga₂O₃ nanocrystals among the glass matrix. Impressively, Eu²⁺ activators were produced after glass crystallization in an air atmosphere, and the Cr³⁺ emitting center was evidenced to incorporate into Ga₂O₃ crystalline lattice. As a result, temperature determination with high sensitivity of 0.8% K^–1, large energy gap of 8500 cm^–1, and superior thermal stability were realized by taking advantage of the fluorescence intensity ratio between Eu²⁺ and Cr³⁺ as detecting parameter, which exhibited a linear dependence on temperature. We believe that this preliminary investigation will provide a practical approach for developing a high-performance self-calibrated optical thermometer

Four new anthraquinones from a soil actinomycete <i>Streptomyces</i> sp. WS-13394 and their bioactivities

<p>Further chemical study of secondary metabolites from the soil actinomycete <i>Streptomyces</i> sp. WS-13394 resulted in the isolation of four new alkylated anthraquinone analogues (<b>5</b>–<b>8</b>). Their structures were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, 1D and 2D NMR. The new compounds, together with analogues obtained before (<b>1</b>–<b>4</b>), were tested for their <i>in vitro </i>cytotoxicity against Huh-7 and SGC-7901.</p