A time-resolved luminescence spectroscopy study of non-linear optical crystals K 2Al 2B 2O 7

Abstract

We report the results of complex study of luminescence and dynamics of electronic excitations in K 2Al 2B 2O 7 (KABO) crystals obtained using low-temperature luminescence-optical vacuum ultraviolet spectroscopy with sub-nanosecond time resolution under selective photoexcitation with synchrotron radiation. The paper discusses the decay kinetics of photoluminescence (PL), the time-resolved PL emission spectra (1.26.2 eV), the time-resolved PL excitation spectra and the reflection spectra (3.721 eV) measured at 7 K. On the basis of the obtained results three absorption peaks at 4.7, 5.8 and 6.5 eV were detected and assigned to charge-transfer absorption from O 2- to Fe 3+ ions; the intrinsic PL band at 3.28 eV was revealed and attributed to radiative annihilation of self-trapped excitons, the defect luminescence bands at 2.68 and 3.54 eV were separated; the strong PL band at 1.72 eV was revealed and attributed to a radiative transition in Fe 3+ ion. © 2012 Elsevier B.V.