Effect of La and Mo co-doping on the properties of AgSnO₂ contact material

For the shortage of the AgSnO₂ contact material, the models of SnO₂, La–SnO₂, Mo–SnO₂, and La–Mo–SnO₂ were built to calculate their electrical and mechanical properties based on the first principles of density functional theory in this study. The La-Mo co-coped SnO₂ is the most stable of all the models according to the enthalpy change and the impurity formation energy. By analyzing the energy band structure and density of states, the doped models are still the direct bandgap semiconductor materials. The valence band moves up and the conduction band moves down after doped, reducing the band gap and enhancing the conductivity. With the reduced energy for carrier transition, the electrical performance of La-Mo co-doped SnO₂ is improved best. The mechanical properties of SnO₂ were completely improved by La-Mo co-doping with the calculation results. The doped SnO₂ materials were prepared by sol-gel method and the doped AgSnO₂ materials were prepared by powder metallurgy method. The x-ray diffraction experiment, hardness, conductivity and wettability experiment had been taken. And the experimental results show that the AgSnO₂ can be improved comprehensively by La-Mo co-doping, verifying the conclusions of the simulation. It provides an effective method for the preparation of high-performance contact materials. (paper)