Laser Desorption Ionization Time-of-Flight Mass Spectrometry of Silver-Doped (GeS2)50(Sb2S3)50 Chalcogenide Glasses

Abstract

Mass spectra of (GeS₂)₅₀(Sb₂S₃)₅₀ glass and Ag-doped glasses [5% Ag (GeS₂)₅₀(Sb₂S₃)₅₀ and 15% Ag (GeS₂)₅₀(Sb₂S₃)₅₀] obtained using laser desorption ionization (LDI) time-of-flight coupled with quadrupole ion trap mass spectrometry were studied. The analysis of the mass spectra indicated the formation of Ag _a Ge _b Sb _c S _d clusters. In addition to the SbS _d ⁺ (d = 1 and 2), Sb₂S _d ⁺ (d = 1-3), Sb₃S _d ⁺ (d = 1-5), Sb₄S _d ⁺ (d = 3 and 4), Sb₅S₂ ⁺, and Sb _c ⁺ (c = 3 and 5) clusters, various clusters containing Ag, such as Ag _a ⁺ (a = 1 and 2), AgGeS⁺, AgSb _c ⁺ (c = 1, 2, and 4), AgSbS⁺, AgSb₂S _d ⁺ (d = 1-5), AgSb₃S₃ ⁺, AgSb₄S₄ ⁺, Ag₂Sb₃S _d ⁺ (d = 4 and 5), Ag₄Sb₂S₃ ⁺, and Ag₅SbS₃ ⁺, were generated. Moreover, in spite of the five-ninth purity of all glass components, several hydrogenated clusters (SbS₃H₈ ⁺, Sb₄S₂H⁺, Ag₂H₁₁ ⁺, Ag₂Sb₃H₄ ⁺, Ag₃Sb₂H₄ ⁺, Ag₄Sb₂H₂ ⁺, and Ag₄S₃H₈ ⁺) and some low-intensity oxidized clusters, such as Sb₃O⁺ and Sb₃O₅ ⁺, were also detected. When applying LDI on (GeS₂)₅₀(Sb₂S₃)₅₀ glass, no Ge-containing clusters were detected in the positive ion mode, and just one Ge-containing cluster was observed after doping the glass with Ag. Hydrogen plays an important role in the glasses studied. The knowledge gained concerning cluster stoichiometry contributes to the elucidation of the structure of Ag-doped Ge-Sb-S chalcogenide glasses. It should be noted that some of the clusters were considered to be structural fragments. Furthermore, mass spectrometry was complemented with Raman spectroscopy.