Structural and optical properties of ER3+ doped tellurite glass with copper oxide nanoparticles embedment.

Abstract

Improving the optical properties of copper oxide nanoparticles (CuO NPs) in tellurite glass is crucial for the development of efficient solid state laser. In this work, we report the results of structurally-induced transitions in melt-quench synthesized CuO NPs integrated Er2O3 doped multicomponent tellurite glasses. Based on the predecessors’ work, we optimized the components of such glasses to observe its effects on the structural, physical and optical properties of the glasses were characterized using density, XRD, HTEM, FTIR, UV–vis-IR absorption and PL spectroscopy. The variations of physical properties are measured and the hardness of the glasses is performed by using Vickers Microhardness. XRD analysis confirmed the amorphous nature of the prepared glass sample. The presence of CuO NPs is verified by using HRTEM with lattice spacing 0.23 nm at (111) plane orientation inside the glass matrix. FTIR spectrum shows that the glasses are made up of [TeO4] and [TeO3] structural units. Absorption spectra of glasses consisted of seven significant bands from the ground sate 4I15/2 to the excited states 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2 and 4I13/2 are attributed to excited states around 488, 522, 545, 652, 799, 973 and 1530 nm, wherein 4I15/2 to 4I9/2 transition in Er3+ disclosed the highest intensity. The decrease in bonding parameter increases the formation of more covalent bond in the glass network. Appreciable changes have been observed in the photoluminescence emission intensity with the change in Cu NPs concentration in the medium. Down-conversion emission spectra under 380 nm excitation shows four peaks centered at 408, 530, 550, and 660 nm. Meanwhile, up-conversion emission spectra under excitation 980 nm shows three peaks centered at 530, 550, and 660 nm. The enhancement in the luminescence is attributed to the localized electric field in vicinity of nanoparticles, while, the quenching effect is responsible from the large formation of multipoles interaction that leads to the energy transfer from RE ions to NPs. Intense green emission obtained from the proposed glasses could be a potential gain medium for solid-state laser medium.