Effect of Sr Doping on Electrical Transport and Emission of 12CaO·7Al 2O 3 Electride

【Author】

ZHAO Wei-Kang;ZHANG Xin;FENG Qi;ZHAO Ji-Ping;LIU Hong-Liang;LI Fan;XIAO Yi-Xin;LIU Yan-Qin;ZHANG Jiu-Xing

【Institution】

Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology;School of Materials Science and Engineering, Hefei University of Technology

【Abstract】

[Ca 24Al 28O 64] 4+:4e ? (C12A7:e ?) is a new cathode material with low working temperature and low work function, and its unique cage structure attracts the attention of researchers. In this work, the Sr doped (C 1? x S x )12A7:e ? (0 ≤ x ≤ 0.05) was prepared by the high-temperature solid-phase reaction combined with spark plasma sintering (SPS), and the electron compound (Ca 1? x Sr x )12A7:e ? was successfully obtained by reduction of Ti particles at 1 100 °C for 20 h. The first-principles calculations for electronic structure show that Sr doping changes the band structure of C12A7:e ?, and the Framework Conduction Band (FCB) decreases to 0.3 eV, which benefits the electrical properties of (Ca 1? x Sr x )12A7:e ?. The total density of states (DOS) of (Ca 1? x Sr x )12A7:e ? near the Fermi level is increased. The electrical transport characteristics test results show that the (Ca 0.96Sr 0.04)12A7:e ? has the highest conductivity 1 136 S/cm and carrier concentration (2.13 ± 0.11) × 10 21 cm ?3, indicating that Sr doping is beneficial for reducing the preparation time of mayenite electride. The thermionic emission performance test results show that Sr doping significantly increases the emission current density and effectively reduces the average effective work function. The (Ca 0.96Sr 0.04)12A7:e ? has the best emission performance, and the emission current density reaches 1.45 A/cm 2 at 1 100 °C and an anode voltage of 3 500 V. The zero-field emission current density is 0.74 A/cm 2, and the Richardson work function reduces from 2.01 eV (un-doped) to 1.86 eV.

【Keywords】

C12A7:e ? electride;Sr doping;electrical transport;emission performance

References

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Total: 3 articles

  • [1] Feng Qi;Zhang Xin;Liu Hong-Liang;Zhao Ji-Ping;Jiang Hao;Xiao Yi-Xin;Li Fan;Zhang Jiu-Xing;Key Laboratory of Advanced Functional Materials, Ministry of Education, College of Materials Science and Engineering,Beijing University of Technology;School of Materials Science and Engineering, Hefei University of Technology;, Fabrication and electrical transport characteristics of the polycrystalline Ca_(12)Al_(14)O_(33)electride, Acta Physica Sinica,
  • [2] Lu Gong;;Zhou Lin;;Shen Ning;;Jianqiu Sun;;Jing Shen;;Youshifumi Torimoto;;Quanxin Li, Synthesis and characteristics of the C12A7-O ? nanoparticles by citric acid sol–gel combustion method, Materials Letters,
  • [3] Ryoji Kiyanagi;;James W. Richardson;;Naonori Sakamoto;;Masahiro Yoshimura, Free oxygen ions and cage deformation in the nanoporous material 12CaO·7Al 2 O 3 : A temperature-dependent neutron powder diffraction study, Solid State Ionics,