A time-resolved luminescence spectroscopy study of non-linear optical crystals K2Al2B2O7

• Published in: Journal of luminescence 2012-07, Vol.132 (7), p.1632-1638
• Main Authors: Ogorodnikov, I.N., Pustovarov, V.A., Yakovlev, S.A., Isaenko, L.I., Zhurkov, S.A.
• Format: Article
• Language: English
• Subjects: Band spectra; Crystal defects; Crystals; Decay; Defects; Electronics; Excitation spectra; K2Al2B2O7 (KABO); Luminescence; Luminescence decay kinetics; Luminescence excitation spectra; Luminescence spectra; Nonlinear crystal; Nonlinear dynamics
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2012.02.032

We report the results of complex study of luminescence and dynamics of electronic excitations in K2Al2B2O7 (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 (1.2–6.2eV), the time-resolved PL excitation spectra and the reflection spectra (3.7–21eV) measured at 7K. On the basis of the obtained results three absorption peaks at 4.7, 5.8 and 6.5eV were detected and assigned to charge-transfer absorption from O2− to Fe3+ ions; the intrinsic PL band at 3.28eV was revealed and attributed to radiative annihilation of self-trapped excitons, the defect luminescence bands at 2.68 and 3.54eV were separated; the strong PL band at 1.72eV was revealed and attributed to a radiative transition in Fe3+ ion. ► Charge-transfer absorptions from O2− to Fe+ were revealed at 4.7, 5.8 and 6.5eV. ► From reflection spectrum at 7K the bandgap Eg was estimated as 7.8–8.2eV. ► Intrinsic PL at 3.28eV originates from annihilation of self-trapped exciton. ► Strong PL band at 1.72eV originates from a radiative transition in Fe3+ ion. ► PL bands at 2.68 and 3.54eV originate from Fe3+ associated with lattice defects.