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Optical manometry is a highly promising method for measuring pressure. However, its wider application is limited by the lower sensitivity and influenced by environmental factors. Herein, multi‐mode optical pressure sensors based on Eu2+‐doped Li4SrCa(SiO4)2 phosphors suitable for a variety of complex pressure‐measuring environments are designed. The phosphors contain two separate luminescence centers at 443 nm (EuSr) and 584 nm (EuCa), respectively. In the lower pressure range, the emission peak undergoes a massive redshift of 5.19 nm GPa−1 of EuCa, which is 14× better than commercially available ruby sensors. In order to improve the pressure response range and the accuracy of pressure measurement, for the first time, a new approach in the pressure readout method in which single Eu2+ ions doping based on fluorescence intensity ratio (FIR) pressure measurement is realized in designed materials. Meanwhile, the measured full width at half maximum (FWHM) as an indicator of pressure sensor performance also reveals that the sensing performance is d FWHM/d P ≈ 1.23 nm GPa−1 and d FWHM/d P ≈ 0.84 nm GPa−1 for EuSr and EuCa positions, respectively. Additionally, the structural stability of the phosphor is confirmed by in situ Raman spectrum. The above results indicate that the Li4SrCa(SiO4)2:0.04Eu2+ phosphor is a good candidate for multi‐mode optical pressure sensors. [ABSTRACT FROM AUTHOR]

In this work, a method for controllable regulation of crystal form was proposed for the first time and the effects of different crystal forms on the up‐conversion luminescence properties of Ho3+, Yb3+ co‐doped K3Sc0.5Lu0.5F6 (KSLF) phosphors was explored. KSLF:Ho3+, Yb3+ phosphors were synthesized by the high temperature solid‐state reaction method, and X‐ray diffraction (XRD) results illustrate that the compounds can obtain monoclinic phase and cubic phase at different synthesis temperatures. In addition, according to the power‐dependent up‐conversion luminescence (UCL) intensity, the UCL mechanism and the electronic transition process are discussed. Simultaneously, the temperature sensing behavior of the best samples with different crystal forms at different temperatures was studied by fluorescence intensity ratio technique. All the results show that KSLF:Ho3+, Yb3+ phosphors show great application potential in the field of temperature sensing, and the preparation of KSLF:Ho3+, Yb3+ in different crystal forms can provide a reference value for crystal design and growth. [ABSTRACT FROM AUTHOR]

Pyroxene‐type phosphors were widely developed due to the advantages of high chemical stability, luminous efficiency, and low production cost. In this contribution, a series of Eu2+/Tb3+ co‐doped Ca0.75Sr0.2Mg1.05Si2O6 (CSMS) phosphors with pyroxene structure were successfully synthesized by the solid‐state method. Under the 340 nm excitation, the emission peaks of the phosphor show a redshift with the increase of Eu2+ concentration. The emitting color of Eu2+/Tb3+ co‐doped samples shows a redshift attributed to the energy transfer from Eu2+ to Tb3+. Simultaneously, acquired thermometer exposes superbly temperature‐sensitive properties (Sa and Sr having maximum values 4.7% K−1 and 0.6% K−1, respectively) over the cryogenic temperature range (77–280 K). Furthermore, it has good stability and precision at cryogenic temperatures, indicating that CSMS:0.03Eu2+/0.03Tb3+ phosphor is a very promising fluorescent material suitable for cryogenic temperature sensing. [ABSTRACT FROM AUTHOR]

A switchable and filter‐free photonic microwave single‐sideband frequency converter based on a dual‐parallel dual‐drive Mach‐Zehnder modulator is proposed and experimentally demonstrated. Two first‐order carrier‐suppression single sidebands for input signal and local oscillator signal are achieved by adjusting the DC bias voltages of the modulator. The frequency upconversion and downconversion can be switched by adjusting one DC bias voltage of the modulator. Thanks to the carrier‐suppression single‐sideband modulation without using any filter, the frequency converter has a large operating bandwidth but no power fading caused by chromatic dispersion, and the mixing spurs can be effectively suppressed. Experimental results show that the frequency converted signal is pure over a wide frequency range, and the sideband suppression ratio of desired signal is over 20 dB. The spur free dynamic range achieves 108.3 dB Hz2/3. [ABSTRACT FROM AUTHOR]

Abstract: A systematic study on the metabolome differences between wild Ophiocordyceps sinensis and artificial cultured Cordyceps militaris was conducted using liquid chromatography−mass spectrometry. Principal component analysis and orthogonal projection on latent structure‐discriminant analysis results showed that C. militaris grown on solid rice medium (R‐CM) and C. militaris grown on tussah pupa (T‐CM) evidently separated and individually separated from wild O. sinensis, indicating metabolome difference among wild O. sinensis, R‐CM and T‐CM. The metabolome differences between R‐CM and T‐CM indicated that C. militaris could accommodate to culture medium by differential metabolic regulation. Hierarchical clustering analysis was further performed to cluster the differential metabolites and samples based on their metabolic similarity. The higher content of amino acids (pyroglutamic acid, glutamic acid, histidine, phenylalanine and arginine), unsaturated fatty acid (linolenic acid and linoleic acid), peptides, mannitol, adenosine and succinoadenosine in O. sinensis make it as an excellent choice as a traditional Chinese medicine for invigoration or nutritional supplementation. Similar compositions with O. sinensis and easy cultivation make artificially cultured C. militaris a possible alternative to O. sinensis. [ABSTRACT FROM AUTHOR]

Single-phase KLaSr3( PO4)3F: Sm3+ phosphors with fluorapatite structure were prepared via high-temperature solid-state method in air atmosphere for the first time. The X-ray diffraction, scanning electron microscope, diffuse reflectance spectra, photoluminescence spectra, and temperature-dependent emission spectra, as well as lifetimes were measured to characterize the as-prepared phosphors. Phase results indicated that KLaSr3( PO4)3F: Sm3+ belongs to hexagonal system with a space group of P-6. Photoluminescence measurements showed the emission spectrum was composed of four sharp peaks at about 564, 602 (the strongest one), 646, and 702 nm, corresponding to the 4G5/2-6 H J ( J=5/2, 7/2, 9/2, and 11/2) transitions of Sm3+ ions. The optimum doping concentration of Sm3+ ions was turned out to be 0.03 (mol), and the mechanism of energy transfer among Sm3+ ions was considered to be dipole-dipole interaction by using Dexter's theory. In addition, the critical distance Rc for energy transfer among Sm3+ ions were calculated to be 9.97 Å according to Blasse concentration quenching method. The selected KLa0.97Sr( PO4)3F: 0.03Sm3+ exhibited high thermal stability with an activation energy of 0.163 eV. Besides, the Commission International de l'Eclairage chromaticity coordinate of the phosphor were located in the orange-reddish light region. [ABSTRACT FROM AUTHOR]

Traditional luminescent materials commonly exhibit single‐duration emissions and single‐timed emissions with limited emission peaks. Developing a material with multicolor, variable temporal, and multimodal luminescence is a significant challenge. Self‐reduction phosphors have attracted considerable interest for their distinctive properties and versatile applications. Distinguished by their rigid structure and exceptional purity, offer a safer alternative to conventional reduction methods using hazardous gases H2/CO/N2. However, synthesizing these phosphors with precise control over self‐reduction and defect regulation is complex. Therefore, innovative structures and substrates are essential to address these challenges. This review discusses the latest developments in phosphors doped with ions such as Eu3+, Mn4+, Ce4+, and Yb3+, examining the origins and advancements in self‐reduction. It covers classifications, mechanisms, defects, and applications, with an emphasis on techniques for controlled self‐reduction through structural and charge transfer modifications. This work aims to provide valuable insights to facilitate further research and innovation endeavors. [ABSTRACT FROM AUTHOR]

Single-phase Ba10-x-y (PO4)6O:xEu2+,yMn2+ phosphors are prepared by solid state reaction of stoichiometric mixtures of BaCO3, NH4H2PO4, Eu2O3, and MnCO3 (alumina crucibles, flowing 10% H2/90% N2, 1200 °C, 5 h). [ABSTRACT FROM AUTHOR]

Sr10(PO4)6O:Eu2+x (x = 0.005-0.07) is prepared by solid state reaction of stoichiometric amounts of SrCO3, (NH4)2HPO4, and Eu2O3 in a reducing atmosphere of 5% H2/N2 (alumina crucible, 1300 °C). [ABSTRACT FROM AUTHOR]

The title phosphors are prepared by solid state reactions of SrCO3, SiO2, CeO2, La2O3, and Tb4O7 (alumina crucible, flowing 5%H2/95%N2, 1350 °C, 5 h). [ABSTRACT FROM AUTHOR]