为研究Sb掺杂对Ti/SnO2电极稳定性与导电性的影响,采用基于密度泛函理论的平面波赝势方法对金红石型SnO2及不同比例Sb掺杂SnO2体系进行了第一性原理计算,用广义梯度近似方法优化了Sn1-xSbxO2固溶体电极的晶体结构,计算了掺杂前后体系的电子结构以及不同掺杂比例时的形成能.结果表明:Sb替代Sn后,晶格常数与晶胞体积均增加,但掺杂形成能随掺杂量变化不大,在掺杂量为0.083时掺杂形成能达到最低值5.08eV,稳定性最好.掺杂Sb后,在费米能级至最低导带处存在Sb5s电子态分布,产生施主能级;同时Sb掺杂后,在导带底形成的可填充电子数也从未掺杂的4增加到了掺杂后的19,导电性明显增强,且在掺杂量为0.063时导电性最强.本文的计算结果为钛基Sn1-xSbxO2氧化物电极的开发与应用提供了理论依据.
A theoretical study on Sb-doped SnO2 was carried out using a plane wave pesudopotential schene density functional theory (DFT) at the generalized gradient approximation (GGA) level.Stability and conductivity analyses were performed based on the formation energy of doping and the electronic structures.Results show that the SnO2 lattice constants expand into a distorted rutile structure as the antimony content increases.The formation energy of doping shows little change as the doping ratio changes and it has a minimum value of 5.08 eV at a doping ratio of 0.083.This suggests that the Sn0.917Sb0.083O2 solid solution has the highest stability.Density of state (DOS) calculations showed that a Sb 5s distribution of electronic states exists from the Fermi level to the lowest conduction band after doping with antimony.In addition,19 electrons were present in the lowest conduction band after doping compared to 4 electrons before doping.This results in the increased conductivity of the solid solution.At a doping ratio of 0.063,the Sn0.937Sb0.063O2 solid solution had the strongest conductivity.These results provide a theoretical basis for the development and application of Sn1-xSbxO2 solid solution electrodes.