Emission Properties of Reduced Graphene Oxide-Coated Er3+-tellurite Glass for Fiber Optics

In this work, reduced graphene oxide-coated zinc borotellurite doped with erbium oxide nanoparticles denoted as ZBTEr (NPs)-rGO was studied as an approach to enhance the optical properties of glass materials. Herein, a melt-quenched technique was used to prepare the ZBTEr (NPs) glasses. A simple and inexpensive spray-coated technique was employed to deposit the rGO onto the glass surfaces directly. The morphological studies of ZBTEr (NPs)-rGO glass surfaces were investigated by scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HR-TEM) meanwhile, the structural investigation of ZBTEr (NPs) glasses was revealed by X-ray diffraction (XRD) and Raman analysis. The morphological analysis revealed the residual oxygen groups functionalized on ZBTEr (NPs)-rGO glass surfaces meanwhile, TEM images confirmed the presence of Er (NPs) in the glassy matrix. The glass samples showed the existence of structural disorder and amorphous nature. The absorption spectra presented the transition bands that existed from 4I15/2 ground state level to excited state levels of 2H9/2, 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I11/2, and 4I9/2, respectively. Judd–Ofelt analysis was performed to obtain the intensity parameters (Ωλ), radiative transition (A), branching ratios (βR), and radiative lifetimes (tr). The radiative parameter and branching ratio values suggested the higher stimulated emission radiative at 2H11/2 → 4I15/2 transition for present glass The luminescence spectra exhibited two emission peaks centred at 539 nm and 558 nm which were assigned to 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions, respectively. The optical results for ZBTEr (NPs)-rGO and ZBTEr (NPs)-uncoated were compared to determine the differences between coated and uncoated glasses. These results highlight the significant effect of rGO deposited onto tellurite-based glass and thus, this work proposed the potential coating materials for improving current fiber optics.