Bi_(2)Te_(3)块体的高压氢/氮气烧结与热电性能研究

Thermoelectric Properties of Bi_(2)Te_(3) Bulks Sintered in High-Pressure H_(2) and N_(2) Atmosphere

采用自制高气压热处理系统在不同的压力和时间下,以高压氢气或氮气烧结的方法制备Bi_(2)Te_(3)块体。晶格和形貌的表征及热电性能测试结果表明:Bi_(2)Te_(3)块体在高压40MPa、H_(2)氛围下烧结后发生P-N型转变;由于H原子进入Bi_(2)Te_(3)晶胞或晶胞间隙,增加声子散射,降低热导率;样品Bi_(2)Te_(3)在高压40MPa、N_(2)氛围烧结后,电导率最大达到1265S/cm;样品Bi_(2)Te_(3)在高压65MPa、N_(2)氛围烧结后,室温下热电优值最大提高到0.6;高压氢气/氮气烧结是提高Bi_(2)Te_(3)块体热电性能的有效方法。

Bi_(2)Te_(3) bulks were prepared by high pressure hydrogen or nitrogen sintering under different pressure and different time using a self-made high pressure heat treatment system.After the characterization of the lattice and morphology of the system and the test of the thermoelectric properties,the results show that the P-N type transformation of Bi_(2)Te_(3) bulk occurs after sintering at high pressure of 40 MPa and H_(2) atmosphere.In addition,because H atoms enter Bi_(2)Te_(3) cell or intercellular space,phonon scattering is increased and thermal conductivity is reduced.The maximum conductivity of sample Bi_(2)Te_(3) is 1265 S/cm after sintering at high pressure 40 MPa and N_(2) atmosphere.The ZT value of Bi_(2)Te_(3) is increased to~0.6 at room temperature after sintering at 65 MPa and N_(2) atmosphere.Therefore,high pressure hydrogen/nitrogen sintering is a simple and effective method to improve the thermoelectric properties of Bi_(2)Te_(3) bulks.