Effects of Er3+:Ag codoping on structural and spectroscopic properties of lead tellurite glass ceramics

Structural, spectroscopic and optical properties of lead tellurite glass ceramics doped with variable amounts of erbium ions and codoped with fixed amounts of silver (Ag2O or Ag metallic nanoparticles, AgNPs) have been studied. The investigation of the samples was performed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), diffuse reflectance ultraviolet–visible (DR-UV–vis) and photoluminescence (PL) spectroscopies. The average unit-cell parameter, crystallite size and the quantitative ratio of the crystallographic phases in the samples were evaluated from the XRD data. FTIR spectroscopy data show that the glass ceramics network mainly consists of TeO3 and TeO4 structural units. The increase of the Er2O3 content determines a TeO3→TeO4 conversion but the process is also influenced by the nature of the codopant (Ag2O or AgNPs) present in the samples. The optical band gap View the MathML source(Egopt) values, determined from the DR-UV–vis spectra, decrease with increasing the erbium content of the samples. Photoluminescence spectroscopy measurements evidenced the important peaks located at around 430 nm and 708 nm due to the Pb2+ ions and at 525 and 547 nm due to the Er3+ ions present in the studied samples. The Er3+:Ag codoping was found to produce antagonistic effects (quenching/enhancement) of the luminescence emission of Er3+ ions in the studied samples.