用溶剂热法合成了二元Bi2Te3和三元Bi1.3Sn0.7Te3合金纳米粉末,并采用热压技术制备了块状热电材料。XRD分析结果表明:Bi Sn Te三元固溶体合金可以直接通过溶剂热合成获得单相产物,而非掺杂Bi2Te3合金需要通过热压等后热处理来实现产物...用溶剂热法合成了二元Bi2Te3和三元Bi1.3Sn0.7Te3合金纳米粉末,并采用热压技术制备了块状热电材料。XRD分析结果表明:Bi Sn Te三元固溶体合金可以直接通过溶剂热合成获得单相产物,而非掺杂Bi2Te3合金需要通过热压等后热处理来实现产物的单一化;热压过程有助于促进反应的完全和晶型的完整,但会导致晶粒的长大。对试样电导率σ和Seebeck系数α的测量结果显示,Bi Sn Te三元固溶体合金比二元Bi Te合金具有更好的电学性能。展开更多
The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is d...The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is demonstrated that the thermoelectric performances are significantly affected by the porous structure, especially for the electrical and thermal conductivity due to the enhanced carrier scattering and phonon scattering. The increasing porosity resulted in the obvious decrease in electrical and thermal conductivity, and little change in Seebeck coefficients. It is encouraging that the reduction of thermal conductivity can compensate for the deterioration of electrical performance, leading to the enhancement in thermoelectric figure of merit(ZT). The maximum ZT value of 1.0 was obtained for the sample with a relative density of 90% at 333 K. Unfortunately, the increase in porosity also brought in obvious degradations in Vickers hardness from 51.71 to 27.74 HV. It is worth mentioning that although the Vickers hardness of the sample with a relative density of 90% decreased to 40.12 HV, it was still about twice as high as that of the zone melting sample(21.25 HV). To summarize, introducing pores structure into bulks properly not only enhances the ZT value of BiTebased alloys, but also reduces the use of raw materials and saves production cost.展开更多
（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） thermoelectric material was sintered via a field activated and pressure assisted sintering（FAPAS） process.By applying different current intensity（0,60,320 A/cm^2） in the si...（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） thermoelectric material was sintered via a field activated and pressure assisted sintering（FAPAS） process.By applying different current intensity（0,60,320 A/cm^2） in the sintering process,the effects of electric current on the microstructure and thermoelectric performance were investigated.This demonstrated that the application of electric current in the sintering process could significantly improve the uniformity and density of（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） samples.When the current intensity was raised to 320 A/cm^2,the preferred orientation of grains was observed.Moreover,positive effects on the thermoelectric performance of applying electric current in the sintering process were also confirmed.An increase of 0.02 and 0.11 in the maximum figure of merit ZT value could be acquired by applying current of 60 and 320 A/cm^2,respectively.展开更多
Use of a flexible thermoelectric source is a feasible approach to realizing selfpowered wearable electronics and the Internet of Things.Inorganic thin films are promising candidates for fabricating flexible power supp...Use of a flexible thermoelectric source is a feasible approach to realizing selfpowered wearable electronics and the Internet of Things.Inorganic thin films are promising candidates for fabricating flexible power supply,but obtaining highthermoelectric‐performance thin films remains a big challenge.In the present work,a p‐type Bi_(x)Sb_(2−x)Te_(3)thin film is designed with a high figure of merit of 1.11 at 393 K and exceptional flexibility(less than 5%increase in resistance after 1000 cycles of bending at a radius of∼5 mm).The favorable comprehensive performance of the Bi_(x)Sb_(2−x)Te_(3)flexible thin film is due to its excellent crystallinity,optimized carrier concentration,and low elastic modulus,which have been verified by experiments and theoretical calculations.Further,a flexible device is fabricated using the prepared p‐type Bi_(x)Sb_(2−x)Te_(3)and n‐type Ag_(2)Se thin films.Consequently,an outstanding power density of∼1028μWcm^(−2)is achieved at a temperature difference of 25 K.This work extends a novel concept to the fabrication of highperformance flexible thin films and devices for wearable energy harvesting.展开更多
为优化碲化铋(Bi_(2)Te_(3))纳米材料的制备工艺,以BiCl_(3)和Na_(2)TeO_(3)为前驱体,乙二醇为溶剂和还原剂,采用搅拌辅助溶剂热合成法制备了六边形Bi_(2)Te_(3)纳米片。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对合成的Bi_(2)Te_(3...为优化碲化铋(Bi_(2)Te_(3))纳米材料的制备工艺,以BiCl_(3)和Na_(2)TeO_(3)为前驱体,乙二醇为溶剂和还原剂,采用搅拌辅助溶剂热合成法制备了六边形Bi_(2)Te_(3)纳米片。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对合成的Bi_(2)Te_(3)纳米片进行物相分析和形貌观察,系统地研究了反应温度、NaOH和聚乙烯吡咯烷酮(PVP)的添加量、搅拌速率及反应时间对合成Bi_(2)Te_(3)纳米片的影响。结果表明上述工艺参数对Bi_(2)Te_(3)纳米片形貌均有显著影响,最终将含有0.315 g BiCl_(3)、0.332 g Na_(2)TeO_(3)、0.4 g NaOH和0.5 g PVP的50 mL乙二醇反应液,以200℃的反应温度和500 r/min的搅拌速率反应4 h,制备出表面光滑、形貌规则、尺寸均匀的六边形Bi_(2)Te_(3)纳米片,纳米片的平均边长约为450 nm。展开更多
文摘用溶剂热法合成了二元Bi2Te3和三元Bi1.3Sn0.7Te3合金纳米粉末,并采用热压技术制备了块状热电材料。XRD分析结果表明:Bi Sn Te三元固溶体合金可以直接通过溶剂热合成获得单相产物,而非掺杂Bi2Te3合金需要通过热压等后热处理来实现产物的单一化;热压过程有助于促进反应的完全和晶型的完整,但会导致晶粒的长大。对试样电导率σ和Seebeck系数α的测量结果显示,Bi Sn Te三元固溶体合金比二元Bi Te合金具有更好的电学性能。
基金supported financially by the National Natural Science Foundation of China(Nos.11074195 and 51674181)the Key Projects of Hubei Provincial Department of Education(No.D20151103)
文摘The porous p-type BiSbTebulks containing irregularly and randomly oriented pores were obtained by artificially controlling the relative density of sintered samples during resistance pressing sintering process. It is demonstrated that the thermoelectric performances are significantly affected by the porous structure, especially for the electrical and thermal conductivity due to the enhanced carrier scattering and phonon scattering. The increasing porosity resulted in the obvious decrease in electrical and thermal conductivity, and little change in Seebeck coefficients. It is encouraging that the reduction of thermal conductivity can compensate for the deterioration of electrical performance, leading to the enhancement in thermoelectric figure of merit(ZT). The maximum ZT value of 1.0 was obtained for the sample with a relative density of 90% at 333 K. Unfortunately, the increase in porosity also brought in obvious degradations in Vickers hardness from 51.71 to 27.74 HV. It is worth mentioning that although the Vickers hardness of the sample with a relative density of 90% decreased to 40.12 HV, it was still about twice as high as that of the zone melting sample(21.25 HV). To summarize, introducing pores structure into bulks properly not only enhances the ZT value of BiTebased alloys, but also reduces the use of raw materials and saves production cost.
基金Project support by the National Research Program of China(No.50975190)
文摘（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） thermoelectric material was sintered via a field activated and pressure assisted sintering（FAPAS） process.By applying different current intensity（0,60,320 A/cm^2） in the sintering process,the effects of electric current on the microstructure and thermoelectric performance were investigated.This demonstrated that the application of electric current in the sintering process could significantly improve the uniformity and density of（Bi_2Te_3）_（0.2）（Sb_2Te_3）_（0.8） samples.When the current intensity was raised to 320 A/cm^2,the preferred orientation of grains was observed.Moreover,positive effects on the thermoelectric performance of applying electric current in the sintering process were also confirmed.An increase of 0.02 and 0.11 in the maximum figure of merit ZT value could be acquired by applying current of 60 and 320 A/cm^2,respectively.
基金National Natural Science Foundation of China,Grant/Award Number:62274112Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2022A1515010929Science and Technology Plan project of Shenzhen,Grant/Award Numbers:JCYJ20220531103601003,20220810154601001。
文摘Use of a flexible thermoelectric source is a feasible approach to realizing selfpowered wearable electronics and the Internet of Things.Inorganic thin films are promising candidates for fabricating flexible power supply,but obtaining highthermoelectric‐performance thin films remains a big challenge.In the present work,a p‐type Bi_(x)Sb_(2−x)Te_(3)thin film is designed with a high figure of merit of 1.11 at 393 K and exceptional flexibility(less than 5%increase in resistance after 1000 cycles of bending at a radius of∼5 mm).The favorable comprehensive performance of the Bi_(x)Sb_(2−x)Te_(3)flexible thin film is due to its excellent crystallinity,optimized carrier concentration,and low elastic modulus,which have been verified by experiments and theoretical calculations.Further,a flexible device is fabricated using the prepared p‐type Bi_(x)Sb_(2−x)Te_(3)and n‐type Ag_(2)Se thin films.Consequently,an outstanding power density of∼1028μWcm^(−2)is achieved at a temperature difference of 25 K.This work extends a novel concept to the fabrication of highperformance flexible thin films and devices for wearable energy harvesting.
文摘为优化碲化铋(Bi_(2)Te_(3))纳米材料的制备工艺,以BiCl_(3)和Na_(2)TeO_(3)为前驱体,乙二醇为溶剂和还原剂,采用搅拌辅助溶剂热合成法制备了六边形Bi_(2)Te_(3)纳米片。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对合成的Bi_(2)Te_(3)纳米片进行物相分析和形貌观察,系统地研究了反应温度、NaOH和聚乙烯吡咯烷酮(PVP)的添加量、搅拌速率及反应时间对合成Bi_(2)Te_(3)纳米片的影响。结果表明上述工艺参数对Bi_(2)Te_(3)纳米片形貌均有显著影响,最终将含有0.315 g BiCl_(3)、0.332 g Na_(2)TeO_(3)、0.4 g NaOH和0.5 g PVP的50 mL乙二醇反应液,以200℃的反应温度和500 r/min的搅拌速率反应4 h,制备出表面光滑、形貌规则、尺寸均匀的六边形Bi_(2)Te_(3)纳米片,纳米片的平均边长约为450 nm。
