A novel, contactless optical sensor of pressure based on the luminescence red-shift and bandwidth (full width at half-maximum, fwhm) of the Ce 3+ -doped fluorapatite-Y 6 Ba 4 (SiO 4 ) 6 F 2 powder has been successfully synthesized via a facile solid-state method. The obtained material exhibits a bright blue emission under UV light excitation. It was characterized using powder X-ray diffraction, scanning electron microscopy and luminescence spectroscopy, including high-pressure measurements of excitation and emission spectra, up to above ∼30 GPa. Compression of the material resulted in a significant red-shift of the allowed 4f → 5d and 5d → 4f transitions of Ce 3+ in the excitation and emission spectra, respectively. The pressure-induced monotonic shift of the emission band, as well as changes in the excitation/emission band widths, have been correlated with pressure for sensing purposes. The material exhibits a high pressure sensitivity (dλ/dP ≈ 0.63 nm/GPa) and outstanding signal intensity at high-pressure conditions (∼90% of the initial intensity at around 20 GPa) with minimal pressure-induced quenching of luminescence. KEYWORDS: Ce 3+ doping, contactless pressure gauge, compression in DAC, lanthanide ions (Ln 3+ ), luminescent functional materials, Y 6 Ba 4 (SiO 4 ) 6 F 2 apatite phosphors

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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 4G5/2‐6HJ (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.

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A novel single-phase white light emitting phosphor Ca9La(PO4)5(SiO4)F2:Dy3+ was prepared through traditional high-temperature solid state technology.