Ultralow thermal conductivity in In2O3 mediated by porous structures
Ultralow thermal conductivity in In2O3 mediated by porous structures
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多孔结构介导的 In2O3 超低导热率
DOI：
10.1016/j.micromeso.2019.05.050
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发表时间：
2019-11-01
影响因子：
5.2
通讯作者：
Tan, X. F.
中科院分区：
文献类型：
--
作者：
Du, K.;Deng, S. P.;Tan, X. F.
以50 ℃和100 ℃下合成的KIT-6为模板剂，分别制备了两种不同孔径的介孔In 2 O3（分别命名为50 ℃-In 2 O3和100 ℃-In 2 O3）。小角X射线散射和透射电子显微镜测量都证实了有序的孔结构在合成的In 2 O3。N-2吸附/脱附分析表明，这两种In 2 O3的孔径分别约为11.06 nm和8.737 nm。正电子寿命测量表明在多孔In 2 O3样品中存在微孔和介孔，并且在100 ° C-In 2 O3中的介孔尺寸小于在50 ° C-In 2 O3中的介孔尺寸。50度C-In 2 O3和100度C-In 2 O3的孔隙率分别为约44%和40%。与商业In 2 O3纳米粉末在900 ℃高温下SPS烧结得到的块状In 2 O3相比，多孔In 2 O3的热导率降低了一个数量级以上。对于100摄氏度的In 2 O3，在25摄氏度的室温下，热导率低至0.58 Wm（-1）K（-1），这低于非晶极限。另一方面，多孔In 2 O3的导电性被孔结构恶化，但它部分地被塞贝克系数的增加所补偿。对于50 ℃的In 2 O3，在300 ℃时的总ZT因子增加到高于0.08，这几乎是体In 2 O3的三倍。
Two mesoporous In2O3 were prepared with different pore size by using KIT-6 template synthesized at temperature of 50 degrees C and 100 degrees C (designated as 50 degrees C-In2O3 and 100 degrees C-In2O3), respectively. Small angle X-ray scattering and transmission electron microscope measurements all confirm ordered pore structure in the synthesized In2O3. N-2 adsorption/desorption analysis indicates that the pore size in these two In2O3 is about 11.06 nm and 8.737 nm, respectively. Positron lifetime measurements suggest existence of both micropores and mesopores in the porous In2O3 samples, and the mesopore size in 100 degrees C-In2O3 is smaller than that in 50 degrees C-In2O3. The porosity of 50 degrees C-In2O3 and 100 degrees C-In2O3 is about 44% and 40%, respectively. Comparing with the bulk In2O3 obtained by SPS sintering of the commercial In2O3 nanopowders at high temperature of 900 degrees C, the thermal conductivity of porous In2O3 decreases by more than an order of magnitude. For the 100 degrees C-In2O3, the thermal conductivity is as low as 0.58 Wm(-1)K(-1) at room temperature of 25 degrees C, which is below the amorphous limit. On the other hand, the electrical conductivity of the porous In2O3 is deteriorated by the pore structure, but it is partially compensated by the increase of Seebeck coefficient. The overall ZT factor increases to higher than 0.08 at 300 degrees C for 50 degrees C-In2O3, which is almost three times that of the bulk In2O3.