碳纳米管纱的时间依赖电性能(英文)

Time-dependent electrical properties of carbon nanotube yarns

碳纳米管(CNTs)在电力转换领域具有潜在前景。本文表征碳纳米管纱随时间变化对电力的转换性能影响。通过建立I-V关系,结果表明存在3个区域,即线性、非线性和下降区域。线性区域表明呈现低且恒定电阻。当恒定电压处于I-V线性区域时,输出电流强度不随时间而改变。然而,当恒定电压处于非线性区域时,电流强度以指数级下降后随时间而趋平。在恒电流测试下,电压仅在电流强度处于非线性区时增加。依赖时间的导电性能可通过短路来理解。短路发生在非线性区域的碳纳米管纱中炽热部位,会导致热性能降低。通过热图像、热重分析、扫描电镜和能谱分析等手段对碳纳米管纱进行分析。

Carbon nanotubes （ CNTs） are projected as a desirable option to transmit electrical power where specific conductivity is an important consideration. A CNT-yarn was therefore characterized for its ability to transmit power as a function of time. A current-voltage （ I-V） relationship was established that showed three distinct regions： linear, non-linear and finally its degradation. The linear region shows a low and constant resistance. The output current did not change with time when the applied constant voltage was in the linear region of the I-V relationship. However, when the applied constant voltage was in the non-linear region the current decreased exponentially and leveled off with time. Under constant current tests, voltage increased only when current level was in the non-linear region. These time-dependent electrical conducting properties can be accounted for by short circuits occurring from the development of a localized red-hot spots in the CNT-yarn in the non-linear region, leading to thermal degradation, as revealed by thermal imaging of the yarn, thermal gravimetric analysis of the CNTs, and SEM images and EDAX of the thermally degraded CNT-yarn.