Jia Caihong, Yang Feng, Zhao Lei, Cheng Gang, Yang Guanghong
Henan Key Laboratory of Photovoltaic Materials, School of Physics and Electronics, Henan University, Kaifeng, 475004, People's Republic of China.
Key Lab for Special Functional Materials of Ministry of Education, Henan University, Kaifeng, 475004, People's Republic of China.
Nanoscale Res Lett. 2019 Jan 8;14(1):10. doi: 10.1186/s11671-018-2844-3.
Understanding the electrical transport properties of individual nanostructures is of great importance to the construction of high-performance nanodevices. NiCoO nanowires have been investigated widely as the electrodes in electrocatalysis, supercapacitors, and lithium batteries. However, the exact electrical transport mechanism of an individual NiCoO nanowire is still ambiguous, which is an obstacle for improving the performance improvement of energy storage devices. In this work, NiCoO nanowires were prepared successfully by thermal transformation from the CoNi-hydroxide precursors. The electrical transport properties of an individual NiCoO nanowire and its temperature-dependent conduction mechanisms were studied in detail. The current-voltage characteristics showed that an ohmic conduction in a low electrical field (< 1024 V/cm), Schottky emission in a middle electric field (1024 V/cm < E < 3025 V/cm), and Poole-Frenkel conduction at a high electric field (> 3025 V/cm). A semiconductive characteristic is found in the temperature-dependent conductivity in the NiCoO nanowire; the electrical conduction mechanism at low temperature (T < 100 K) can be explained by Mott's variable range hopping (VRH) model. When the temperature is greater than 100 K, electrical transport properties were determined by the VRH and nearest neighbor hopping (NNH) Model. These understandings will be helpful to the design and performance improvement of energy-storage devices based on the NiCoO nanowires.
了解单个纳米结构的电输运特性对于构建高性能纳米器件至关重要。NiCoO纳米线作为电催化、超级电容器和锂电池中的电极已被广泛研究。然而，单个NiCoO纳米线的确切电输运机制仍不明确，这是提高储能器件性能的一个障碍。在这项工作中，通过从CoNi氢氧化物前驱体进行热转变成功制备了NiCoO纳米线。详细研究了单个NiCoO纳米线的电输运特性及其与温度相关的传导机制。电流-电压特性表明，在低电场（<1024 V/cm）下为欧姆传导，在中等电场（1024 V/cm < E < 3025 V/cm）下为肖特基发射，在高电场（>3025 V/cm）下为普尔-弗伦克尔传导。在NiCoO纳米线的电导率与温度的关系中发现了半导体特性；低温（T < 100 K）下的导电机制可以用莫特变程跳跃（VRH）模型来解释。当温度高于100 K时，电输运特性由VRH和最近邻跳跃（NNH）模型决定。这些认识将有助于基于NiCoO纳米线的储能器件的设计和性能提升。
