Liu Li-Feng, Lee Seung-Woo, Li Jing-Bo, Alexe Marin, Rao Guang-Hui, Zhou Wei-Ya, Lee Jae-Jong, Lee Woo, Gösele Ulrich
Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle, Germany.
Nanotechnology. 2008 Dec 10;19(49):495706. doi: 10.1088/0957-4484/19/49/495706. Epub 2008 Nov 19.
AgI nanowires/anodic aluminum oxide (AgI NWs/AAO) composites have been fabricated by a simple approach, which involves the thermal melting of AgI powders on the surface of the AAO membrane, followed by the infiltration of the molten AgI inside the nanochannels. As-prepared AgI nanowires have corrugated outer surfaces and are polycrystalline according to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. X-ray diffraction (XRD) shows that a considerable amount of 7H polytype AgI exists in the composites, which is supposed to arise from the interfacial interactions between the embedded AgI and the alumina. AC conductivity measurements for the AgI nanowires/AAO composites exhibit a notable conductivity enhancement by three orders of magnitude at room temperature compared with that of pristine bulk AgI. Furthermore, a large conductivity hysteresis and abnormal conductivity transitions were observed in the temperature-dependent conductivity measurements, from which an ionic conductivity as high as 8.0 × 10(2) Ω(-1) cm(-1) was obtained at around 70 °C upon cooling. The differential scanning calorimetry (DSC) result demonstrates a similar phase transition behavior as that found in the AC conductivity measurements. The enhanced ionic conductivity, as well as the abnormal phase transitions, can be explained in terms of the existence of the highly conducting 7H polytype AgI and the formation of well-defined conduction paths in the composites.
通过一种简单的方法制备了碘化银纳米线/阳极氧化铝（AgI NWs/AAO）复合材料，该方法包括将AgI粉末在AAO膜表面进行热熔，然后使熔融的AgI渗透到纳米通道内部。根据扫描电子显微镜（SEM）和透射电子显微镜（TEM）观察，所制备的AgI纳米线具有波纹状外表面且为多晶结构。X射线衍射（XRD）表明，复合材料中存在大量的7H多型AgI，这可能源于嵌入的AgI与氧化铝之间的界面相互作用。与原始块状AgI相比，AgI纳米线/AAO复合材料的交流电导率测量结果显示，在室温下电导率显著提高了三个数量级。此外，在与温度相关的电导率测量中观察到了较大的电导率滞后和异常的电导率转变，冷却时在约70°C时获得了高达8.0×10²Ω⁻¹cm⁻¹的离子电导率。差示扫描量热法（DSC）结果表明其相变行为与交流电导率测量中发现的相似。离子电导率的提高以及异常的相变可以用高导电的7H多型AgI的存在以及复合材料中形成明确的传导路径来解释。
