介质辅助脉冲激光蒸发法制备巨磁阻聚苯胺纳米复合薄膜及机理研究

Recently, it’s a technical challenge and scientific problem to fabricate the functional organic magnetoresistive thin films with the high magnetoresistance and high magnetic field sensitivity for the giant magnetoresistance applications. This work aims to prepare the organic magnetoresistive polyaniline (PANI) and its nanocomposite thin films with the high magnetoresistance and high magnetic field sensitivity at room temperature by the combination of surface initiated polymerization method and matrix-assisted pulsed laser evaporation (MAPLE) method through the optimization of polymerization conditions, the types of nanofillers, and the parameters control of MAPLE. Based on the wave-function shrinkage model and forward interference model, the mechanism of magnetoresistive effect in the PANI and its nanocomposite thin films would be investigated and the factors influencing the giant magnetoresistance of PANI and its nanocomposite thin films would be systematically evaluated. The structure-activity relationship and theoretical models for the PANI and its nanocomposite thin films would be established. The obtained results would provide a new method and theoretical fundamental for the synthesis of novel functional organic magnetoresistive PANI and its nanocomposite thin films with optimal structures and properties and guide the applications of these organic semiconductors in the giant magnetoresistance sensors.

目前，如何制备出具有高磁电阻率、高磁场灵敏度的有机半导体功能薄膜，并应用于巨磁阻设备已成为目前亟需解决的技术难点和科学问题。本项目提出采用表面引发聚合和介质辅助脉冲激光蒸发相结合的方法，通过优化聚合工艺条件、筛选纳米填充物种类和调控介质辅助脉冲激光参数，设计制备在室温下具有高磁电阻率、高磁场灵敏度的有机半导体巨磁阻聚苯胺及其纳米复合薄膜。同时，基于波函数坍缩理论和正向干涉理论模型相结合的探讨分析，揭示其产生巨磁阻效应的机理，系统评价有机半导体聚苯胺纳米复合薄膜巨磁阻性能影响因素，建立聚苯胺及其纳米复合薄膜组成结构与特征性能之间的构效关系和理论模型，为设计优化性能优异的有机半导体巨磁阻聚苯胺及其纳米复合薄膜提供一种新方法和理论指导，并为实现该类材料在巨磁阻设备领域的工程化应用建立研究基础。

巨磁阻效应的发现和自旋电子学的进步促进了新型自旋电子器件的开发和应用。相比于传统的无机半导体材料，有机半导体材料由于具有质量轻、性能可调性强、柔韧性好、成本低廉等优点以及丰富的电学、磁学和光学等特性，逐渐成为传统无机半导体材料的替代品，被用来研制集磁、电和光为一体的新型柔性多功能有机自旋电子器件。因此，如何制备出具有巨磁阻效应的有机半导体功能薄膜，并应用于巨磁阻设备已成为目前亟需解决的技术难点和科学问题。本项目通过采用表面引发聚合方法和介质辅助脉冲激光蒸发法相结合的方法，在经过聚合工艺条件的优化和介质辅助脉冲激光参数的调控后，制备出了在室温下具有一定巨磁阻效应的有机半导体聚苯胺及其纳米复合薄膜。实验结果表明，采用机械搅拌和超声分散方法相结合制备的聚苯胺/铁酸钴纳米复合材料在室温下具有较高的巨磁阻效应，最高为-35.7%。将其用于介质辅助脉冲激光蒸发法制备聚苯胺/铁酸钡纳米复合薄膜，在激光能量为294mJ、沉积时间为1h的参数条件下，制备的薄膜较为均匀，巨磁阻效应为-6%。本项目的研究结果为实现有机半导体薄膜材料在巨磁阻设备领域的应用提供了一定的理论研究依据和研究基础。