Optical properties of 3d transition metal ion-doped aluminophosphate glasses

Abstract

P2O5–Al2O3–SiO2-GeO2-Li2O glasses doped with 3 d-transition metal (TM) ions from Sc to Zn were prepared by the conventional melting-quenching method. Their optical properties were investigated. The oxidation states, which were revealed from the UV–vis–NIR transmittance spectra, excitation and emission spectra of the studied glasses, are Sc(III), Ti(III), V(III), Cr(III), Mn(II), Fe(II,III), Co(II), Ni(II), Cu(I, II) and Zn(II). Scandium exhibits weak, broad emission at 321 nm in aluminophosphate glass probably ascribed to the formation of the ScAl center. Cr3+ emission at 890 nm due to the 4T2(4F)→4A2(4F) transition of Cr3+ ions at the weak crystal field octahedral sites was observed under excitation at 296, 457, 658, and 684 nm. Mn2+ emission at 603 nm with a distinct shoulder at ∼513 nm due to the 4T1(4G) → 6A1(6S) transition of Mn2+ ions in an octahedral coordination and tetrahedral coordination environment, respectively, were observed under excitation at 346 nm and 408 nm. Cu+ emission at 468 nm with excitation at around 290 nm was ascribed to transition from excited s state to ground d state (d9s→d10) of Cu+. No other 3dN TM ions are found to give strong visible emission in aluminophosphate glass at room temperature. Temperature dependent emission spectra for V, Cr, Mn, Fe, Cu doped aluminophosphate glass with laser excitation have also been investigated.