The n-type nonstoichiometric PbTe(Pb0.55Te0.45) materials were prepared by the high pressure sintering process. The emphasis of the present study is on the influence of the pressure on the thermoelectric properties of the material. The experimental results show that the lattice defects are removed by high pressure sintering process, and it effectively adjusts the carrier concentration and its transport properties. Compared with the melting ingots, the Seebeck coefficient of the high pressure sintering sample obtains enhancement largely, the electric conductivity slightly reduces, simultaneously the thermal conductivity is low, and therefore the figure of merit (Tα2σ/κ) of the high pressure sintering sample is greatly enhanced. Therefore, the maximum the figure of merit of the sample prepared by 2 GPa reaches 0.59 at 700 K, which is about 150% improvement in comparison with the melting ingot.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |