Long-lasting phosphorescence in Sn[sup 2+]–Cu[sup 2+] codoped silicate glass and its high-pressure treatment effect.

Long-lasting phosphorescence was observed at 510 nm in a Sn[sup 2+] -Cu[sup 2+] codoped Na[sub 2]O-CaO-SiO[sub 2] glass at room temperature under UV illumination of 254 nm. When the glass was compressed under 3, 6, and 9 GPa, the phosphorescence shifted to 465 nm and its decay rate became shorter. The optical absorption spectra of the samples changed after compression, showing that the cupric ions were reduced to the cuprous ions. The high-pressure treatment also resulted in a lower-energy shift in the absorption edge. It was suggested that Sn[sup 2+] ions act as hole trapping centers, while oxygen vacancies surrounding by Ca[sup 2+] ions as well as active sites in the glass matrix, i.e., as electron trapping centers. [ABSTRACT FROM AUTHOR]