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首页> 外文期刊>Physical review >Density functional theory study on the electronic structure of n- and p-type doped SrTiO_3 at anodic solid oxide fuel cell conditions
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Density functional theory study on the electronic structure of n- and p-type doped SrTiO_3 at anodic solid oxide fuel cell conditions

机译:阳极固体氧化物燃料电池条件下n型和p型掺杂SrTiO_3电子结构的密度泛函理论研究

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摘要

The electronic conductivity and thermodynamic stability of mixed n-type and p-type doped SrTiO_3 have been investigated at anodic solid oxide fuel cell (SOFC) conditions using density functional theory (DFT) calculations. In particular, constrained ab initio thermodynamic calculations have been performed to evaluate the phase stability and reducibility of various Nb- and Ga-doped SrTiO_3 at synthesized and anodic SOFC conditions. The density of states (DOS) of these materials was analyzed to study the effects of n- and p-doping on the electronic conductivity. In agreement with experimental observations, we find that the transformation from 20% Nb-doped Sr-deficient SrTiO_3 to a non-Sr-deficient phase occurs at high temperature and low oxygen partial pressure, which leads to a significant improvement in electronic conductivity. A mixed ionic/electronic conductor is obtained when doping 20% Nb-doped SrTiO_3 with small amounts of Ga (10%) in a reducing environment and high temperature. Doping with higher concentrations of Ga, e.g., 20%, diminishes the electronic conductivity of the material. These findings suggest that independent of the specific dopant, mixed ionic/electronic conductivity can be obtained in perovskite oxides under reducing conditions and high temperatures by doping the B-site with small amounts of both n-type and p-type dopants.
机译:利用密度泛函理论(DFT)计算研究了n型和p型混合掺杂SrTiO_3在阳极固体氧化物燃料电池(SOFC)条件下的电导率和热力学稳定性。特别地,已经进行了从头算的热力学计算,以评估在合成和阳极SOFC条件下各种Nb和Ga掺杂的SrTiO_3的相稳定性和可还原性。分析了这些材料的状态密度(DOS),以研究n和p掺杂对电子电导率的影响。与实验观察一致,我们发现在高温和低氧分压下会发生从20%掺Nb的Sr缺陷型SrTiO_3到非Sr缺陷相的转变,这导致电子电导率显着提高。在还原性环境和高温下,用少量Ga(10%)掺杂20%Nb掺杂的SrTiO_3可获得混合的离子/电子导体。掺杂较高浓度的Ga,例如20%,会降低材料的电子导电性。这些发现表明,在钙钛矿氧化物中,可以通过在还原条件和高温下通过向B位掺杂少量的n型和p型掺杂剂来获得与离子掺杂剂无关的混合的离子/电子电导率。

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  • 来源
    《Physical review》 |2011年第20期|p.205102.1-205102.9|共9页
  • 作者单位

    Department of Chemical Engineering, University of South Carolina, 301 South Main Street, Columbia, South Carolina 29208, USA;

    Department of Chemical Engineering, University of South Carolina, 301 South Main Street, Columbia, South Carolina 29208, USA;

    Department of Mechanical Engineering, University of South Carolina, 300 South Main Street, Columbia, South Carolina 29208, USA;

    Department of Mechanical Engineering, University of South Carolina, 300 South Main Street, Columbia, South Carolina 29208, USA;

    Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, USA;

    Department of Chemical Engineering, University of South Carolina, 301 South Main Street, Columbia, South Carolina 29208, USA;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    other inorganic compounds; other crystalline inorganic semiconductors;

    机译:其他无机化合物;其他晶体无机半导体;

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