Correlated phase and microstructural evolution are systematically investigated by electron microscopies in Sr-deficient Sr(Ti,Nb)O_(3)(STNO)thermoelectric ceramics incorporated with different fraction of reduced graph...Correlated phase and microstructural evolution are systematically investigated by electron microscopies in Sr-deficient Sr(Ti,Nb)O_(3)(STNO)thermoelectric ceramics incorporated with different fraction of reduced graphene oxide(RGO).It is found that while no impurity except for very few Ti_(3)O_(5) precipitates are observed in monolithic STNO,the Nb-enriched rutile TiO_(2) appears in RGO/STNO composites.With increasing RGO content,the amount of precipitates increase at first and then decrease when RGO content becomes high,which can be ascribed to the formation of local Magneli phase.In addition,the energy-dispersive X-ray spectra combined with cathodoluminescence characterization indicates that the variation of Sr deficiency experiences the opposite trend with respect to the precipitates content.These findings clearly reveal the unique reducing effect of RGO on the microstructure of doped SrTiO_(3) with Sr deficiency,which can greatly facilitate the design of perovskite based thermoelectric materials of hierarchical structure.展开更多
基金supported by the National Natural Science Foundation of China[Grant numbers 51532006,51432004]State Administration of Foreign Experts Affairs of China,111 project[Grant number D16002]the Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(Grant number KLIFMD201804).
文摘Correlated phase and microstructural evolution are systematically investigated by electron microscopies in Sr-deficient Sr(Ti,Nb)O_(3)(STNO)thermoelectric ceramics incorporated with different fraction of reduced graphene oxide(RGO).It is found that while no impurity except for very few Ti_(3)O_(5) precipitates are observed in monolithic STNO,the Nb-enriched rutile TiO_(2) appears in RGO/STNO composites.With increasing RGO content,the amount of precipitates increase at first and then decrease when RGO content becomes high,which can be ascribed to the formation of local Magneli phase.In addition,the energy-dispersive X-ray spectra combined with cathodoluminescence characterization indicates that the variation of Sr deficiency experiences the opposite trend with respect to the precipitates content.These findings clearly reveal the unique reducing effect of RGO on the microstructure of doped SrTiO_(3) with Sr deficiency,which can greatly facilitate the design of perovskite based thermoelectric materials of hierarchical structure.
