Spectral selectivity of luminescence of a copper ion-exchange layer in sodium-potassium-magnesium silicate glass

The bright luminescence of the copper ion-exchange layer in glass has potential applications as a converter of electric spark and corona discharge radiation in devices for the rapid analysis of metals because of its selectivity. The selectivity of the luminescence of the copper ion-exchange layer was achieved by the presence of different luminescent centers within it. In this work, the copper monomers, Cu⁺-Cu⁺ monovalent dimers, and Cu_n molecular clusters were formed in an ion-exchange layer of sodium-potassium-magnesium silicate glass (SiO₂-Na₂O-CaO-MgO-Al₂O₃-K₂O-Fe₂O₃). The luminescence of the copper ion exchange layer was characterized by steady-state spectroscopy and time-resolved spectroscopy. Molecular copper clusters Cu_n exhibited luminescence in the nanosecond range, and Cu⁺ monomers and Cu⁺-Cu⁺ monovalent dimers in the microsecond range, respectively. At the same time the formation of divalent copper led to a limitation in the duration of ion exchange for the production of luminescent glasses. Heat treatment of the ion-exchange layers led to an increase in the concentration of molecular copper clusters, Cu⁺-Cu⁺ monovalent dimers, and Cu²⁺ divalent monomers.