大长径比有序碲基纳米线薄膜热电性能研究及柔性器件构筑

Thermoelectric materials, an environmentally friendly clean energy, meet the demand of China’s new energy development strategy with a prosperous application in thermoelectric power generation and refrigeration, which has attracted great attention. One-dimensional (1D) nanowires with a large surface-to-volume ratio, owing to their quantum size effect, show excellent thermoelectric performance. Presently, telluride nanowires (MTe, M=Bi, Sb, Pb, Cu, etc.) show better thermoelectric performance compared to bulk telluride material, however, a further improvement is still needed. Ordered nanowire films show unique optical, magnetic, and electronic properties, which is expected to be an effective approach in order to gain a more excellent thermoelectric performance. Nevertheless, few researches focus on the thermoelectric performance of ordered nanowire films. The project design to synthesized telluride nanowires with a large aspect ratio (˃1000) by the common hydrothermal method. Well-defined single and multilayered telluride nanowire films can be produced by the induced interfacial self-assembly technology, including the Langmuir-Blodgett and solvent evaporation. The key techniques and the effects of nanowire orientation with a large area of ordered nanowire films will be studied systematically on thermoelectric performance. This design desires to achieve a good thermoelectric performance for the large aspect ratio of telluride nanowires. After self-assembly, the well-defined ordered telluride nanowire films have a higher conductivity, thermopower, and electronic transfer properties. Eventually, the relative information will be obtained by the investigation of thermoelectric performance with different nanowire scales and orientations in order to provide supports for highly thermoelectric performance of nanowire films. Additionally, accomplishment of this project will provide valuable theoretic foundation and experimental support for the development of novel flexible thermoelectric conversion device based on ordered nanowire thin-films.

大长径比和有序结构一维纳米线材料的尺寸效应能有效改善电子传输性能，有望获得更优异的热电性能，在该领域仍是研究空白。碲化物纳米线(MTe, M= Bi, Sb, Pb, Cu等)具有优于常规材料的热电性能，仍需进一步改善。本项目拟先采用水热法一步合成大长径比(˃1000)碲纳米线，通过优化合成过程中的溶度、温度、时间、pH值等条件，掌握长径比可控的制备技术，再利用阳离子交换法制备碲化物纳米线。利用朗格缪尔-布吉特或溶剂蒸发界面诱导技术，筛选溶剂实现纳米线在气-水界面上的单层分散，有效控制压缩或挥发溶剂的速率，从而组装大长径比有序碲化物纳米线薄膜。系统探索纳米线排列取向对热电性能的影响，获得有序结构热电传输的实际数据和理论依据，研究不同层数有序碲化物纳米线柔性薄膜的热电性能，并构筑小型柔性薄膜热电转换器件。本项目对于探索大长径比有序纳米线薄膜热电材料性能的提高具有重要的理论和实践意义。

大长径比和有序结构一维纳米线材料的尺寸效应能有效改善电子传输性能，有望获得更优异的热电性能，在该领域仍是研究空白。. 本项目拟以水热法制备大长径比碲化物纳米线，通过界面诱导方法，组装有序结构碲化物纳米线薄膜。围绕纳米线薄膜热电性能的关键科学问题，系统研究大长径比纳米线的制备条件，探寻有序结构纳米线界面组装的关键技术及其影响因素，探索有序碲化物纳米线薄膜电子传输和热传导对薄膜热电性能的影响，优化有序纳米线薄膜的制备方法、结构及性能，实现复合薄膜热电性能的有效调控，设计和构筑小型薄膜热电转换器件。. 该项目研究获得了平均直径˂10 nm，长径比˃1200的碲纳米线可控制备的关键技术，制备了高质量n和p型两种柔性碲化物(Te, AgTe, SnTe, AuTe)纳米线薄膜。在此基础上，通过简单的电偶交换反应实现了p型碲纳米线向p和n型AgTe纳米线的转换，在75 K温差下可达到65 mV的输出电压。研究了以葡萄糖作为绿色还原剂制备碲纳米线。系统地研究了水热反应温度和反应时间对碲纳米线形貌的影响，不同的水热反应温度和温度均能得到长径比均一、形貌良好的碲纳米线。项目还探索了有序碲纳米线薄膜的组装方法。将制备好的碲纳米线分散在三氯甲烷和三氯甲烷与N,N-二甲基甲酰胺的混合溶液中，通过Langmuir-Blodgett技术分别在PET和玻璃表面成膜。构筑了相应的柔性热电装换器件，获得了Te基复合薄膜和纤维以及高分子热电性能有效调控(化学和电化学)方法，揭示了提升材料热电性能的方式。. 本研究从而有效改善纳米线薄膜的电子传输性能，进一步探讨有序纳米线结构对材料热电转换性能的影响及规律，及其复合薄膜材料热电性能研究，初步实现小型柔性薄膜热电器件的组装，降低碲化物热电转换器件组装的成本，为实际薄膜热电器件的设计和组装提供更充足的理论指导和实验支持。