ИСТИНА

Abstract—Lanthanide (Ln3+) doped materials have proven to be the most efficient candidates for obtaining visible or UV-lasers applicable in data storage. Among the Ln3+ doped materials, Ln3+ doped glasses present a good chemical durability, a potentially excellent mechanical and thermal stability. In the present work a complex impact of rare earth elements and gold nanoparticles (AuNPs) on optical properties of the lead silicate glass is investigated. The optical absorption and photoluminescence (PL) experiments were carried out using К2О-(0,5 – 2,2)PbO-(5,5-13,5)SiO2 glasses containing (0,15 – 0,20)Ln2O3 (Ln = Gd, Er,) and Au-doped (Au). Four types of glasses have been prepared: (i) glasses of base composition, (ii) glasses containing Ln, (iii) glasses doped with Au and (iv) glasses codoped with Ln and Au. The starting batch for glass melting was composed of K2CO3, KNO3, Pb3O4 and SiO2. Then, Ln2O3 (6,20 % wt, batch mass included), Au (0,02%, batch mass excluded) as H[AuCl4] with SnO2 (0,05%, batch mass excluded) or both were added. The glass was melted in an alumina crucible at 1400°C for 4 hours, then poured and quenched into 7-10 mm thick disks with further annealing in a muffle furnace at 450°C for 30 min. As ICP-MS analyses showed, Ln and Au content are 1,2 and 2,0 times, respectively, less than expected numbers due to the partial evaporation of the components. Since Au doped glass remained colourless after annealing it is obvious that there were no AuNPs in it. Formation and growth of AuNPs were induced by thermal activation at 600°C (striking). As a result the glass obtained red colouration. It was observed that AuNPs formation in Ln3+ doped glass occurred spontaneously without additional heat treatment (self-striking). Optical absorption spectra for AuEr glass showed a broad band (530 nm) referred to plasmon resonance being overlapped with a narrow band 4I15/2 - 2H11/2 transition of Er (520 nm). PL spectra proved that luminescence of erbium is not affected by the presence of AuNPs at all. This result leads to a conclusion that none of the energy-transfer effects described for germanium-tellurite glasses take place in lead-silicate glasses studied. Thus, colour of AuEr glass derives from additive color contributions of Er and AuNPs. Meanwhile it was shown that lanthanide ions give rise to AuNPs formation and cause self-striking of the glass. The color of glasses are characterized in CIE-Lab.