Yellow Photoluminescence Properties of Copper Ion Doped Phase–Separated Glasses in Alkali Borosilicate System

Cu and Sn ion co-doped phase-separated glasses in R 2 O-B 2 O 3 -SiO 2 (R = Na or K) systems were prepared to achieve strong and broad yellow emission under near-UV light irradiation caused by the Cu + clusters. The Cu + clusters were formed in the phase-separated glasses, and the resultant broad yellow emission was obtained under near-UV light irradiation. The Cu and Sn ions were concentrated in R 2 O-B 2 O 3 -rich phase. The Cu + ions became mutually close, thereby forming their clusters. This result agrees with the fact that the emission intensity decreased steeply with the suppression of phase separation because of Al 2 O 3 addition. The emission intensity of the glasses in Na 2 O-B 2 O 3 -SiO 2 system was higher than that of the glasses in the K 2 O-B 2 O 3 -SiO 2 system because the former glass had large free spaces in the Na 2 O-B 2 O 3 -rich phase attributable to the small ionic radius of Na + ions.