TY - JOUR

T1 - A luminescence-optical spectroscopy study of Rb2KTiOF5 single crystals

AU - Pustovarov, V. A.

AU - Ogorodnikov, I. N.

AU - Kozlov, A. V.

AU - Isaenko, L. I.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Large single crystals of Rb2KTiOF5 (RKTF), grown by slow solidification method, were studied (7–400 K) for various types of optical and radiation effects. The optical absorption spectra, the parameters of the Urbach rule at 293 K (σ = 0.24 and EU = 105 meV), the low-temperature reflection spectra (T = 7 K, E = 3.7–22 eV) were determined. The luminescence spectra (1.2–6.2 eV) and luminescence decay kinetics are studied upon excitation by a nanosecond electron beam (PCL), ultraviolet and vacuum ultraviolet light (PL), or X-rays radiation (XRL). PL excitation spectra under selective photoexcitation by synchrotron radiation (E = 3.7–22 eV, T = 7 K), temperature dependences of the intensity of steady-state XRL in different emission bands, as well as thermoluminescence (7–400 K) are studied. In the visible spectral region, we detected three luminescence bands that were attributed to radiative annihilation of intrinsic excitons (2.25 eV), recombination-type luminescence (2.1 eV) and luminescence of higher TiOF5 complexes (1.9 eV). The exponential component with lifetime of about 19 μs was revealed in the PCL decay kinetics at 2.25 eV. The low-energy onset of the intrinsic host absorption Ec = 3.55 eV was determined on the basis of the experimental data obtained. Spectra of optical constants were calculated by the Kramers-Krönig method, the energy of the onset of the interband transitions Eg = 4.2 eV was determined, and the main peaks of the optical spectra were identified.

AB - Large single crystals of Rb2KTiOF5 (RKTF), grown by slow solidification method, were studied (7–400 K) for various types of optical and radiation effects. The optical absorption spectra, the parameters of the Urbach rule at 293 K (σ = 0.24 and EU = 105 meV), the low-temperature reflection spectra (T = 7 K, E = 3.7–22 eV) were determined. The luminescence spectra (1.2–6.2 eV) and luminescence decay kinetics are studied upon excitation by a nanosecond electron beam (PCL), ultraviolet and vacuum ultraviolet light (PL), or X-rays radiation (XRL). PL excitation spectra under selective photoexcitation by synchrotron radiation (E = 3.7–22 eV, T = 7 K), temperature dependences of the intensity of steady-state XRL in different emission bands, as well as thermoluminescence (7–400 K) are studied. In the visible spectral region, we detected three luminescence bands that were attributed to radiative annihilation of intrinsic excitons (2.25 eV), recombination-type luminescence (2.1 eV) and luminescence of higher TiOF5 complexes (1.9 eV). The exponential component with lifetime of about 19 μs was revealed in the PCL decay kinetics at 2.25 eV. The low-energy onset of the intrinsic host absorption Ec = 3.55 eV was determined on the basis of the experimental data obtained. Spectra of optical constants were calculated by the Kramers-Krönig method, the energy of the onset of the interband transitions Eg = 4.2 eV was determined, and the main peaks of the optical spectra were identified.

KW - Electronic structure parameters

KW - Low-temperature reflection

KW - Luminescence spectra

KW - Oxyfluoride RbKTiOF

KW - Thermoluminescence

KW - UV-optical spectroscopy

KW - ELECTRONIC-PROPERTIES

KW - PHASE-TRANSITIONS

KW - Oxyfluoride Rb2KTiOF5

KW - TUNGSTATE

KW - FLUORIDES

KW - FAMILY

KW - CAWO4

KW - OXYFLUORIDE

UR - http://www.scopus.com/inward/record.url?scp=85046010033&partnerID=8YFLogxK

U2 - 10.1016/j.optmat.2018.04.027

DO - 10.1016/j.optmat.2018.04.027

M3 - Article

AN - SCOPUS:85046010033

VL - 80

SP - 47

EP - 56

JO - Optical Materials

JF - Optical Materials

SN - 0925-3467

ER -