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The NaY[(Mo[O.sub.4]).sub.2]:[Yb.sup.3+]/ [Tm.sup.3+] single crystal was grown by the vertical Bridgman method using spontaneous crystallization. After annealing at 850 [degrees]C for 24 h in a muffle furnace under an air atmosphere, the obtained light black crystal became transparent and optically clear. Powder X-ray diffraction (PXRD) confirmed that the as-grown crystal had the structure of scheelite. The segregation coefficients of [Tm.sup.3+] and [Yb.sup.3+] were 0.589 and 0.588, respectively. Under 980 nm excitation, the temperature dependence of the emission intensity of the crystal in the temperature range of 298-473 K was measured. The results show that, because of the thermal quenching effect, the emission intensity decreases as the temperature rises. The possible energy transfer modes between [Yb.sup.3+] and [Tm.sup.3+] ions were analyzed. The emission cross section was calculated to be 1.97 x [10.sup.-20] [cm.sup.2] by the Fuchtabauer-Ladeburg formula, and the fluorescence lifetime was fitted to be 166.67 [micro]s., In recent years, with the rapid development of near-infrared (NIR) optical amplifiers and mid-IR fiber lasers, new rare earth-doped solid IR luminescent materials have attracted great attention (1-5). Among rare [...]

The low‐dimensional organic‐inorganic lead halide compound has garnered significant attention in recent times due to its exceptional optoelectronic properties. However, its application in the field of optoelectronics has been hindered by the toxicity of lead. Here, a novel inorganic‐organic compound [Epy]2[CuBr3] single crystal material with a 0D structure based on Cu(I) is introduced. The single crystal exhibits a broad band yellow luminescence, a significant Stokes shift, and a microsecond‐scale photoluminescence (PL) lifetime, which is mainly attributed to the self‐trapped excitons (STEs) excitation. In addition, the relevant PL spectra are measured at 78–348 K. The photoluminescence intensity decreases with increasing temperature due to strong electro‐phonon coupling. The exciton binding energy Eb of the crystal is 76.43 meV, and the Huang‐Rhys factor S is 40.55. It is worth noting that the crystal also shows a good response to X‐rays. Overall, [Epy]2[CuBr3] displays its good potential. [ABSTRACT FROM AUTHOR]

Ytterbium ion doped calcium niobium gallium garnet crystal (Yb: Ca3 (NbGa)5 O12) was successfully grown by Bridgman method. The structure of the crystal was analyzed by XRD. The crystal is cubic crystal system, and the unit cell parameter a = b = c = 12.471 Å. The crystal was tested by Raman spectroscopy, transmission spectroscopy, absorption and emission spectroscopy, and fluorescence lifetime. The absorption cross section, emission cross section, and gain cross section of the crystal were calculated. The effects of annealing in air on the absorption spectrum, emission spectrum and fluorescence lifetime of the crystal were studied. The absorption cross section at 935 nm before annealing is 1.82 x 10-20 cm², and it decreases to 1.40 x10-20 cm² after annealing. The emission cross section at 1 031 nm before annealing is 0.56 x10-20 cm² and it decreases to 0.40 x 10-20 cm² after annealing. The fluorescence decay time before annealing is 1.42 ms, and it is 1.32 ms after annealing. The results demonstrate that the annealing of Yb:Ca3 (NbGa)5 O12 single crystal in air will adversely affect the laser performance of the crystal.Yb:Ca3(NbGa)5O12 crystal. [ABSTRACT FROM AUTHOR]

CTGS crystals are widely used in the field of high-temperature piezoelectricity because of their excellent piezoelectric properties. In this paper, the Ca2+ lattice of CTGS crystals is replaced by Sr2+ with a larger radius to improve their piezoelectric properties. (Sr0.2Ca0.8)3TaGa3Si2O14 and Ca3TaGa3Si2O14 single crystals with a diameter of 25 mm were grown using the vertical Bridgman method. The full width at half maximum (FWHM) of X-ray rocking curves of SCTGS and CTGS crystals are 57.6′′ and 22.3′′, respectively. It was found that the thermal properties of SCTGS crystals, such as specific heat, thermal diffusion and thermal conduction, are slightly lower than those of CTGS crystals. At room temperature, the dielectric permittivity ε T11 increased from 18.59 to 18.78, and the piezoelectric coefficient d11 also increased from 4.22 pC N−1 to 4.54 pC N−1. The electrical resistivities of the X-cut plates of SCTGS and CTGS crystals are approximately 3.78 × 107 Ω cm and 2.40 × 107 Ω cm at 800 °C, respectively. Therefore, SCTGS will be a promising candidate piezoelectric material in the field of high-temperature sensing. [ABSTRACT FROM AUTHOR]