Estudo do sistema vítreo TeO2–ZnO dopado com Er3+ e nanoestruturado com nanopartículas de Ag: aplicações tecnológicas

Abstract

In This work we synthesize and analyze the optical and structural properties of twogroupsofglass matrices 60TeZn and 80TeZn with nominal compositions 60TeO2.40ZnO(mol%) and80TeO2.20ZnO (mol%), respectively. These glassy matrices were doped with Er2O3 andco-doped with metallic silver: 60TeZn+[xEr2O3+yAg] (weight%) and 80TeZn+[xEr2O3+yAg](weight%), with x=0.0; 1.0 and y=0.0; 0.1; 0.3; 0.5; 0.7; 0.9 and 1.0; aimingat possibletechnological applications, such as thermal sensor and waveguide. In this context, toconfirmthe formation and size of silver nanoparticles (NPs), the samples were analyzedbyatomic/magnetic force microscopy (AFM/MFM). To study the effect of the surfaceplasmonresonance of these NPs on the optical properties of erbium ions (Er 3+ ), the glassysampleswere analyzed by Raman scattering, optical absortion (AO), photoluminescence(PL),photoluminescence with temporal resolution (PLRT). Indeed, fromthe Ramanspectraweidentified the presence of two structural groups TeO2 and TeO4, typical of TeO2 of TeO2based glasses present in these two groups of samples, and we observed that the 60TeZnglassmatrix was the one that presented the highest phonon energy (756 cm-1) when comparedtothe80 TeZn glass matrix (663 cm-1). The spectra AO present the transitions 4I15/2( 4I13/2, 4I11/2,4I9/2, 4F9/2, 2H11/2), characteristics of Er 3+ , as well as the presence of hydroxyl (OH-). Theespectra beyond excitation lines at 378 and 405 nm, have Er 3+ ion emissions around450, 530,538, 553, 560 and 660 nm. In addition, we observed from the PL and PLRTspectrathat theincorporation of silver influenced the emission peaks in the green spectral region, as well asthe lifetime 4S3/2 state of Er 3+ ions which decreases as the samples are excited by a wavelengthclose to the surface plasmon resonance of silver NPs (405 nm). This effect was attributedtothe stimulated emission process that occurred around 540 nm, generated by the emissionofsilver under excitation at 378 and 405 nm. An important factor also evidenced inour studieswas a probable platinum contamination of the crucible during the sample synthesis process. Interms of thermal sensor applications, the 60TeZn1Er1Ag sample showed the highest relativethermal sensitivity, approximately 2.1% C-1 at 30 °C. In addition, we observedthat it waspossible to manufacture waveguides in the samples using a pulsed laser. Finally, fromtheresults obtained, we believe that the samples studied here have great potential toact as thermal sensor, for the manufacture of optical devices such as waveguide, as well asintelecomunication.