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Strontium titanite (SrTiO3), which is an experimentally-friendly thermoelectric material, could be a promising candidate for thermoelectric power generation applications. The theorectical study indicates the co-doping of La and Nb could enhance the thermoelectric performance, however, the thermoelectric figure of merits (ZTs) of SrTiO3are still low because the co-doping process at nano-scale is experimentally difficult to control. Here we report a high performance SrTiO3with La-Nb co-doping, which are prepared by a combination of hydrothermal method and high-efficiency sintering. Nano-scale co-doping is successfully modulated by hydrothermal method, and nano-inclusions precipitate during sintering process, to form complex microstructures. In this case, the electrical and thermal transport properties are optimized simultaneously by doping concentration and dopants type, resulting in a record-high ZT>0.6 at 1000−1100K in the 10mol% La and 10mol% Nb doped SrTiO3bulk materials. The nano-scale modulation doping and microstructure controlling approach validated in the present study should be also applicable for other thermoelectric materials.

Ferroelectric thin films possessing high dielectric breakdown strength (DBS) are attractive materials employed to satisfy the requirements of miniaturization and integration of electronic components, especially for dielectric capacitors with large discharge energy density (W). In this work, it is demonstrated for the first time that high DBSin ferroelectric thin film can be awakened by a low-temperature-poling method. Mn-doped Pb0.97La0.02(Zr0.905Sn0.015Ti0.08)O3(PLZST) relaxor thin films were prepared by using a sol-gel method, as when poled at near liquid nitrogen temperature, its DBSand Wat room temperature are greatly enhanced (nearly doubled) from 1286 kV/cm to 2000 kV/cm, and from 16.6 J/cm3to 31.2 J/cm3, respectively. The high ordering of defect dipoles during the low-temperature-poling process is responsible for the great enhancement of the awakened DBSand the outstanding improvement of the W. It concludes that the low-temperature-poling method can provide a new alternative strategy to strength the DBSand thus to improve the electrical performances of ferroelectric materials for the applications required strong electric fields in many fields, especially for dielectric energy storage, electrocaloric cooling, and energy harvesting, etc.