Preliminary results on the photoluminescence and optically stimulated luminescence in Cu-doped and Ag-doped ZnB2 X4 (B=Li, Na, K: X=Cl, Br) compounds.

Abstract

Photoluminescence, and optically stimulated luminescence in ZnB2 X4 (B; Li,Na,K: X; Cl,Br) compounds doped with Cu+ or Ag+ were studied. Double humped emission bands attributable to the activators were observed in all the samples. The observed photoluminescence of Cu+ and Ag+ could be identified with 3d9 4s1 ↔3d10 and 4d9 5s1 ↔5d10 transitions respectively. The longer wavelength band (400-500nm range) could be attributed to the Cu+ or Ag+ ion replacing alkali ion at the octahedral alkali site whereas short wavelength band (340-400nm range) is attributed to a Cu or Ag ion at tetrahedral zinc site. The short wavelength band was found to be intense compared with long wavelength and gave an indication that most of the Cu or Ag ions prefered a tetrahedral Zn site compared with the octahedral alkali site. All the samples exhibit optically stimulated luminescence (OSL). The sensitivity was found to be lattice dependent. The lowest sensitivity of about 1% compared with Al2 O3 :C was observed in lithium lattices whereas highest the sensitivity of about 290% was observed in the case of Cu-doped ZnNa2 Br4 .