Generation of Au_pAg_qTe_r clusters via laser ablation synthesis using Au-Ag-Te nano-composite as precursor: quadrupole ion-trap time-of-flight mass spectrometry

摘要

RATIONALE: Metal tellurides have applications in various fields of science and technology but only a few gold-silver tellurides have been reported. The laser ablation synthesis (LAS) method allows the preparation of nano-materials from solid substrates. Therefore, this method was selected to synthesise some gold-silver tellurides. METHODS: Laser desorption ionisation quadrupole ion trap time-of-flight mass spectrometry (LDI QIT TOF MS) was used for the generation of new Au_pAg_qTer clusters. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to characterise the materials. The stoichiometry of the clusters generated was determined via collision-induced dissociation (CID) and modeling of isotopic patterns. RESULTS: Chemisorption of gold and silver nano-particles on tellurium powder led to the formation of a new kind of Au-Ag-Te nano-composite. The LDI of this nano-composite yielded nine unary (Ag_q, Te_r), 40 binary (Au_pTe_r and Ag_pTe_r) and 78 ternary clusters. The stoichiometry of these novel Au_pAg_qTer clusters is reported here for the first time. CONCLUSIONS: The new Au-Ag-Te nano-composite was found to be a more suitable precursor for the generation of clusters than the mixtures of the elements. TOF MS was shown to be a useful technique for following the generation of gold-silver tellurides. Knowledge of the cluster stoichiometry could accelerate the further development of novel high-tech materials such as chalcogenide glasses.