| Sb doped tin oxide (ATO) nanometer powders have the characteristics of ordinary ATO and nanosized powders. The materials possess wide applications such as display device, electrochromism, energy efficient structure glass, lithium ion cell, solar energy utilization, electromagnetic shielding, antistatic, and so on. It is significant to make an intensive study of the structure and properties of ATO nanopowders. However, unknown factors still remain until to now, such as the electric conduction mechanism, the effect of doping and calcination temperature on the grain growth as well as conductivity, etc. It is also valuable to explore new approaches for resisting agglomerate and modifying the surface properties of nanopowders.In this work, the coprecipitation process was utilized to prepare ATO nanometer powders. Systematical researches for the dependence of crystallite structure, crystallite size and conductivity on doping concentration and calcining temperature were done. It was found that, under certain condition, the resistivity and particles size of powders abruptly increased. The Raman spectra of ATO nanometer powders were analyzed. The grain growth pattern and energy band model were proposed. The following results were obtained:1. Being calcined at the temperature above 550℃ for 2 hours, the ATO powders with 0～25at%Sb were crystallized. The oxygen vacancy was built into the lattice of powders. The sites of Sn4+ ions in the lattice were substituted by Sb5+ and Sb3+ ions. With the doped Sb concentration as well as calcination temperature increasing, the ratio of Sb3+/Sb5+ rose, this led the crystal cell volume of ATO nanopowders to swell. Yet, when the doping concentration surpasses some range, above ～11at%, the majority of Sb atoms segregated to the crystal boundary or particles surface, which caused the crystal cell volume to decrease. The distribution of Sb atoms at grain boundary or on particles surface might form Sb-O compounds. Only when doping concentration was higher... |
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