Tin telluride(SnTe)overwhelmingly continues to be studied owing to its promising thermoelectric properties,tunable electronic structure,and its potential as an alternate to toxic lead telluride(PbTe)based materials.In...Tin telluride(SnTe)overwhelmingly continues to be studied owing to its promising thermoelectric properties,tunable electronic structure,and its potential as an alternate to toxic lead telluride(PbTe)based materials.In this research,we engineer the electronic properties of SnTe by co-doping Mn and Bi below their individual solubility limit.The First principles density functio nal theory studies reveal that both Bi and Mn introduce resonance states,thereby increasing the density of states near the Fermi level leading to enhanced Seebeck coefficient.This unique combination of using two resonant dopants to introduce flatter bands is effective in achieving higher performance at lower tempe ratures manifesting into a large Seebeck value of~91μV/K at room temperature in the present case.Both elements optimally co-doped results in a very high power factor value of~24.3μW/cmK^(2) at 773 K when compared to other high performance SnTe based materials.A zT of~0.93 at 773 K is achieved by tuning the proportion of the co-dopants Mn and Bi in SnTe.The hardness value of pristine SnTe was also seen to increase after doping.As a result,synergistic optimized doping proves to be a suitable means for obtaining thermoelectric materials of superior characteristics without the need for heavy doping.展开更多
We report a green and facile approach for the synthesis of NiFe2O4(NF)nanoparticles with good crystallinity.The prepared materials are studied by various techniques in order to know their phase structure,crystallinity...We report a green and facile approach for the synthesis of NiFe2O4(NF)nanoparticles with good crystallinity.The prepared materials are studied by various techniques in order to know their phase structure,crystallinity,morphology and elemental state.The BET analysis revealed a high surface area of 80.0 m^2·g^-1 for NF possessing a high pore volume of 0.54 cm^3·g^-1,also contributing to the amelioration of the electrochemical performance.The NF sample is studied for its application in supercapacitors in an aqueous 2 mol·L^-1 KOH electrolyte.Electrochemical properties are studied both in the three-electrode method and in a symmetrical supercapacitor cell.Results show a high specific capacitance of 478.0 F·g^-1 from the CV curve at an applied scan rate of 5 mV·s^-1 and 368.0 F·g^-1 from the GCD analysis at a current density of 1A·g^-1 for the NF electrode.Further,the material exhibited an 88%retention of its specific capacitance after continuous 10000 cycles at a higher applied current density of8 A·g^-1.These encouraging properties of NF nanoparticles suggest the practical applicability in high-performance supercapacitors.展开更多
基金supported by grants from the National Research Foundation(NRF)of Korea(No.2018R1A41A1022260),funded by the Korean government(MSIT)the grant in the form of DST INSPIRE Faculty award from Department of Science and Technology,Government of India。
文摘Tin telluride(SnTe)overwhelmingly continues to be studied owing to its promising thermoelectric properties,tunable electronic structure,and its potential as an alternate to toxic lead telluride(PbTe)based materials.In this research,we engineer the electronic properties of SnTe by co-doping Mn and Bi below their individual solubility limit.The First principles density functio nal theory studies reveal that both Bi and Mn introduce resonance states,thereby increasing the density of states near the Fermi level leading to enhanced Seebeck coefficient.This unique combination of using two resonant dopants to introduce flatter bands is effective in achieving higher performance at lower tempe ratures manifesting into a large Seebeck value of~91μV/K at room temperature in the present case.Both elements optimally co-doped results in a very high power factor value of~24.3μW/cmK^(2) at 773 K when compared to other high performance SnTe based materials.A zT of~0.93 at 773 K is achieved by tuning the proportion of the co-dopants Mn and Bi in SnTe.The hardness value of pristine SnTe was also seen to increase after doping.As a result,synergistic optimized doping proves to be a suitable means for obtaining thermoelectric materials of superior characteristics without the need for heavy doping.
文摘We report a green and facile approach for the synthesis of NiFe2O4(NF)nanoparticles with good crystallinity.The prepared materials are studied by various techniques in order to know their phase structure,crystallinity,morphology and elemental state.The BET analysis revealed a high surface area of 80.0 m^2·g^-1 for NF possessing a high pore volume of 0.54 cm^3·g^-1,also contributing to the amelioration of the electrochemical performance.The NF sample is studied for its application in supercapacitors in an aqueous 2 mol·L^-1 KOH electrolyte.Electrochemical properties are studied both in the three-electrode method and in a symmetrical supercapacitor cell.Results show a high specific capacitance of 478.0 F·g^-1 from the CV curve at an applied scan rate of 5 mV·s^-1 and 368.0 F·g^-1 from the GCD analysis at a current density of 1A·g^-1 for the NF electrode.Further,the material exhibited an 88%retention of its specific capacitance after continuous 10000 cycles at a higher applied current density of8 A·g^-1.These encouraging properties of NF nanoparticles suggest the practical applicability in high-performance supercapacitors.
