The thermoelectric properties of Sr0.61Ba0.39Nb2O6-δ ceramics, reduced in different conditions, are investigated in the temperature range from 323 K to 1073 K. The electrical transport behaviors of the samples are do...The thermoelectric properties of Sr0.61Ba0.39Nb2O6-δ ceramics, reduced in different conditions, are investigated in the temperature range from 323 K to 1073 K. The electrical transport behaviors of the samples are dominated by the thermal-activated polaron hopping in the low temperature range, the Fermi glass behavior in the middle temperature range, and the Anderson localized behavior in the high temperature range. The thermal conductivity presents a plateau at high- temperatures, indicating a glass-like thermal conduction behavior. Both the thermoelectric power factor and the thermal conductivity increase with the increase of the degree of oxygen-reduction. Taking these two factors into account, the oxygen-reduction can still contribute to promoting the thermoelectric figure of merit. The highest ZT value is obtained to be -0.19 at 1073 K in the heaviest oxygen reduced sample.展开更多
Nanowires exhibit excellent thermoelectric performance,due to the stronger quantum confinement and phonon scattering effect compared to bulk materials.However,it is a challenge to accurately evaluate the thermoelectri...Nanowires exhibit excellent thermoelectric performance,due to the stronger quantum confinement and phonon scattering effect compared to bulk materials.However,it is a challenge to accurately evaluate the thermoelectric performance of nanowires.In this paper,the thermoelectric properties of an individual suspended Sb_(2)Se_(3) nanowire have been characterized by comprehensive T-type method,including thermal conductivity,electrical conductivity,Seebeck coefficient and figure of merit.The thermal conductivity increases from 0.57 W/(m·K)to 3.69 W/(m·K)with temperature increasing from 80 K to 320 K.The lattice vibration dominates the heat conduction process,and due to its flawless crystal structure,the thermal conductivity is not lower than the reported values of bulk Sb_(2)Se_(3).The electrical conductivity increases from 7.83 S/m to 688 S/m in the temperature range of 50 K–320 K,which is a great improvement compared with the corresponding bulk value.At 294 K,the Seebeck coefficient of the Sb_(2)Se_(3) nanowire is–1120μV/K and the corresponding figure of merit is 0.064.展开更多
A detailed computational investigation,based on density functional theory,of the interaction of polyani-line(PANI)and graphene nanoribbons(GNRs)with SrTiO_(3) is presented.The adsorption of PANI in var-ious oxidation ...A detailed computational investigation,based on density functional theory,of the interaction of polyani-line(PANI)and graphene nanoribbons(GNRs)with SrTiO_(3) is presented.The adsorption of PANI in var-ious oxidation states and co-adsorption with GNRs is found to be thermodynamically favourable.Ad-sorbed PANI introduces N and C 2p states into the SrTiO_(3) bandgap,while co-adsorption of PANI and GNRs leads to a bridging of the gap and semi-metallic behaviour,thus rendering the electrical properties highly sensitive to the loading of the GNRs/PANI in the composites.Modelling the lattice dynamics of the composites predicts a 68-88%reduction in the lattice thermal conductivity due to reduced phonon group velocities.Taken together,these findings provide insight into the growing number of experimental studies highlighting the enhanced thermoelectric performance of oxide-polymer composites and indicate co-adsorption with graphene as a facile direction for future research.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2013CB632506)the National Natural Science Foundation of China(Grant Nos.51202132 and 51002087)
文摘The thermoelectric properties of Sr0.61Ba0.39Nb2O6-δ ceramics, reduced in different conditions, are investigated in the temperature range from 323 K to 1073 K. The electrical transport behaviors of the samples are dominated by the thermal-activated polaron hopping in the low temperature range, the Fermi glass behavior in the middle temperature range, and the Anderson localized behavior in the high temperature range. The thermal conductivity presents a plateau at high- temperatures, indicating a glass-like thermal conduction behavior. Both the thermoelectric power factor and the thermal conductivity increase with the increase of the degree of oxygen-reduction. Taking these two factors into account, the oxygen-reduction can still contribute to promoting the thermoelectric figure of merit. The highest ZT value is obtained to be -0.19 at 1073 K in the heaviest oxygen reduced sample.
基金the National Key Research and Development Program of China(Grant No.2020YFA0715000)the National Natural Science Foundation of China(NSFC)(Grant Nos.52127816 and 52176078)。
文摘Nanowires exhibit excellent thermoelectric performance,due to the stronger quantum confinement and phonon scattering effect compared to bulk materials.However,it is a challenge to accurately evaluate the thermoelectric performance of nanowires.In this paper,the thermoelectric properties of an individual suspended Sb_(2)Se_(3) nanowire have been characterized by comprehensive T-type method,including thermal conductivity,electrical conductivity,Seebeck coefficient and figure of merit.The thermal conductivity increases from 0.57 W/(m·K)to 3.69 W/(m·K)with temperature increasing from 80 K to 320 K.The lattice vibration dominates the heat conduction process,and due to its flawless crystal structure,the thermal conductivity is not lower than the reported values of bulk Sb_(2)Se_(3).The electrical conductivity increases from 7.83 S/m to 688 S/m in the temperature range of 50 K–320 K,which is a great improvement compared with the corresponding bulk value.At 294 K,the Seebeck coefficient of the Sb_(2)Se_(3) nanowire is–1120μV/K and the corresponding figure of merit is 0.064.
基金NDW thanks the EPSRC DTP competition 2018-19 at the University of Huddersfield for funding(EP/R513234/1)JMS is currently supported by a UKRI Future Leaders Fellowship(MR/T043121/1)+2 种基金previously held a University of Manchester Presidential Fellowship.Calculations were performed on the Orion computing fa-cility and the Violeta HPC at the University of Huddersfield,and the THOMAS and YOUNG facilities at the UK Materials and Molecular Modelling Hub(MMM Hub)which is partially funded by the EPSRC(EP/P020194/1 and EP/T022213/1)via our membership of the UK’s HEC Materials Chemistry Consortium(MCC),which is also funded by the EPSRC(EP/R029431/1 and EP/X035859/1).
文摘A detailed computational investigation,based on density functional theory,of the interaction of polyani-line(PANI)and graphene nanoribbons(GNRs)with SrTiO_(3) is presented.The adsorption of PANI in var-ious oxidation states and co-adsorption with GNRs is found to be thermodynamically favourable.Ad-sorbed PANI introduces N and C 2p states into the SrTiO_(3) bandgap,while co-adsorption of PANI and GNRs leads to a bridging of the gap and semi-metallic behaviour,thus rendering the electrical properties highly sensitive to the loading of the GNRs/PANI in the composites.Modelling the lattice dynamics of the composites predicts a 68-88%reduction in the lattice thermal conductivity due to reduced phonon group velocities.Taken together,these findings provide insight into the growing number of experimental studies highlighting the enhanced thermoelectric performance of oxide-polymer composites and indicate co-adsorption with graphene as a facile direction for future research.
基金supported by the National Key Research and Development Program of China(2018YFB0703600 and 2018YFA0702100)the National Natural Science Foundation of China(51772186,51632005 and 51371194)。
