TY - JOUR

T1 - A luminescence spectroscopy study of new Li2BaAl2F10 single crystal

AU - Pustovarov, V. A.

AU - Ogorodnikov, I. N.

AU - Isaenko, L. I.

AU - Lobanov, S. I.

AU - Goloshumova, A. A.

AU - Naumov, D. Yu

PY - 2018/2/1

Y1 - 2018/2/1

N2 - Large Li2BaAl2F10 single crystals of optical quality were grown using the vertical Bridgman method. X-ray diffraction method was used to determine the crystal structure (orthorhombic symmetry Cmc21), lattice parameters, atomic coordinates. The luminescent properties were investigated using selective photoexcitation by synchrotron radiation (E = 3.7–21 eV, T = 8 K, time integrated and time-resolved spectra) as well as upon excitation with unfiltered X-ray beam (synchrotron radiation or X-ray tube). We revealed both the broadband luminescence at E m = 4.0 eV (E ex=11.72 eV) attributed to the radiative annihilation of self-trapped excitons (STE) and the excitonic-type near-defect luminescence at E m = 3.0–3.2 eV (E ex=11.25 eV) attributed to radiative relaxation of electronic excitations in nonequivalent structural units of the crystal lattice. The fast exponential component with lifetime of 5.6 ns, a low-intensity intermediate component with a lifetime of 75–100 ns, a constant level — pedestal (sum of the micro- and millisecond decay components) were revealed in luminescence decay kinetics. The electronic structure parameters (bandgap E g = 13.0 eV, low-energy onset of the intrinsic host absorption E c = 11.2 eV), the energy threshold for the excitation of STE-luminescence (E th = 11.2 eV) are determined from spectroscopic data. Thermoluminescence (TL) has been studied (90–350 K) using spectral-integral regime. Four partially overlapping TL glow peaks were revealed, their deconvolution was done and thermal activation parameters were determined using TGCD method.

AB - Large Li2BaAl2F10 single crystals of optical quality were grown using the vertical Bridgman method. X-ray diffraction method was used to determine the crystal structure (orthorhombic symmetry Cmc21), lattice parameters, atomic coordinates. The luminescent properties were investigated using selective photoexcitation by synchrotron radiation (E = 3.7–21 eV, T = 8 K, time integrated and time-resolved spectra) as well as upon excitation with unfiltered X-ray beam (synchrotron radiation or X-ray tube). We revealed both the broadband luminescence at E m = 4.0 eV (E ex=11.72 eV) attributed to the radiative annihilation of self-trapped excitons (STE) and the excitonic-type near-defect luminescence at E m = 3.0–3.2 eV (E ex=11.25 eV) attributed to radiative relaxation of electronic excitations in nonequivalent structural units of the crystal lattice. The fast exponential component with lifetime of 5.6 ns, a low-intensity intermediate component with a lifetime of 75–100 ns, a constant level — pedestal (sum of the micro- and millisecond decay components) were revealed in luminescence decay kinetics. The electronic structure parameters (bandgap E g = 13.0 eV, low-energy onset of the intrinsic host absorption E c = 11.2 eV), the energy threshold for the excitation of STE-luminescence (E th = 11.2 eV) are determined from spectroscopic data. Thermoluminescence (TL) has been studied (90–350 K) using spectral-integral regime. Four partially overlapping TL glow peaks were revealed, their deconvolution was done and thermal activation parameters were determined using TGCD method.

KW - Crystallographic structure

KW - Decafluoride LiBaAlF

KW - Electronic structure parameters

KW - Luminescence spectra

KW - Thermoluminescence

KW - Vertical Bridgman method

KW - EXCITATION

KW - RELAXATION

KW - CENTERS

KW - LICAALF6

KW - SELF-TRAPPED EXCITONS

KW - ULTRAVIOLET

KW - Decafluoride Li2BaAl2F10

KW - PURE

KW - VUV SPECTROSCOPY

UR - http://www.scopus.com/inward/record.url?scp=85037695043&partnerID=8YFLogxK

U2 - 10.1016/j.optmat.2017.12.017

DO - 10.1016/j.optmat.2017.12.017

M3 - Article

AN - SCOPUS:85037695043

VL - 76

SP - 1

EP - 10

JO - Optical Materials

JF - Optical Materials

SN - 0925-3467

ER -