Shi Zongmo, Zhang Can, Su Taichao, Xu Jie, Zhu Jihong, Chen Haiyan, Gao Tong, Qin Mengjie, Zhang Ping, Zhang Yi, Yan Haixue, Gao Feng
State Key Laboratory of Solidification Processing, MIIT Key Laboratory of Radiation Detection Materials and Devices, USI Institute of Intelligence Materials and Structure, School of Material Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
NPU-QMUL Joint Research Institute of Advanced Materials and Structure, Northwestern Polytechnical University, Xi'an 710072, P. R. China.
ACS Appl Mater Interfaces. 2020 May 13;12(19):21623-21632. doi: 10.1021/acsami.0c03297. Epub 2020 May 4.
Misfit-layered CaCoO as a p-type semiconductor is difficult to commercialize because of its relatively poor performance. Here, CaLaAgCoO/Ag composites prepared by spark plasma sintering were systematically investigated in terms of La dopant levels and nano-sized Ag compacts. Multiscale microstructures of stacking fault, dislocation, and oxygen vacancy-linked defects could be recognized as an effective strategy for tuning the transport of charge carriers and phonon scattering. An increasing concentration of charge carriers was caused by the introduction of nano-sized Ag particles at the grain boundary. The multiscale structural defects served as phonon scattering centers to reduce the thermal conductivity. Finally, the CaLaAgCoO/Ag sample exhibited a maximum of 0.35 at 1073 K. The results suggest that the interplay of structural defects provides an impetus for a huge improvement in thermoelectric performance.