卟啉修饰氧化石墨烯复合材料的微观结构与非线性光学性能调控研究

To explore the relationship between microscopic structure and nonlinear optical performance and to tune the nonlinear optical performances effectively have important significance for the practical application of nonlinear optical materials. Researches show that graphene oxide and its composite materials is a new kind of nonlinear optical materials. However, there are many oxygen containing groups distributed in graphene oxide disorderly, and there are multiple nonlinear optical mechanisms coexist in composite materials, and this makes the study on the relationship between the microscopic structure and nonlinear optical performance becomes a hotspot and difficulty for graphene oxide and its composite materials. . In this project, we will synthesize graphene oxide-based composites with two elements functionalized by porphyrin. Oxygen content, sheet morphology and protonation of graphene oxide and porphyrin will be tuned flexibly, respectively, by controlling the pH value of the solution, the regulation mechanism of microscopic structure of the materials based on pH value will also be studied. The relationship between the microscopic structure and nonlinear optical performance will be explored by using laser pulses with different width and wavelength, and the thermal effect will be analyzed. The laser beam propagation equation including excited state absorption, two-photon absorption and nonlinear refraction in the medium will be established. The experimental and theoretical basis for tuning the nonlinear optical performances of composites will be obtained, and these results will provide a new way to flexibly tune the nonlinear optical performances of two dimensional composites.

探索材料的微观结构与其非线性光学性能之间的关系，从而对其非线性光学性能进行有效的调控，对于非线性光学材料走向实际应用具有重要意义。氧化石墨烯以及卟啉修饰的氧化石墨烯复合材料是一类新型的非线性光学材料，然而氧化石墨烯中大量含氧基团的无序分布以及复合材料中多种非线性机制共存，使得其微观结构与非线性光学性能之间的关系成为研究的热点和难点。. 本项目中拟构筑卟啉修饰的氧化石墨烯二元复合材料。通过控制溶液的pH值，灵活控制氧化石墨烯的含氧比例、形貌以及卟啉分子的质子化程度，并探索pH 值对材料微观结构的调控机理；采用不同宽度和波长的激光脉冲探索材料的微观结构与非线性光学性能之间的关系，并分析不同脉冲下热效应的影响；建立包含激发态吸收、双光子吸收和非线性折射在内的光束传播方程，获得复合材料非线性光学性能调控的实验和理论依据，为二维复合材料非线性光学性能的灵活调控提供新的思路。

探索材料的微观结构与其非线性光学性能之间的关系，从而对其非线性光学性能进行有效的调控，对于非线性光学材料走向实际应用具有重要意义。本项目中，我们开展了基于质子化方式的卟啉分子非线性调控，基于共价修饰和物理共混两种方式的卟啉-碳纳米材料复合材料的非线性机理及其调控方法研究。主要内容如下：（1）通过将四苯基卟啉（H2TPP）及四苯基锌卟啉（ZnTPP）溶液中添加三氟乙酸，降低溶液pH值，使得 H2TPP和ZnTPP发生了质子化，质子化后非线性吸收大大增强，这也为卟啉分子的非线性增强及调控提供了一条可参考的途径。（2）研究了羟基化的多壁碳纳米管（MWNTs-OH）的光学非线性机制，通过研究MWNTs-OH的Z-scan实验结果对比色皿厚度，及溶剂光物理参数的依赖关系，揭示了该材料的光学非线性及光限幅机制，提出了该类材料进行实验时，得到可靠实验结果的条件；（3）将卟啉材料与不同维度的碳纳米材料、含氧碳纳米材料（MWNTs、氧化石墨烯、氨基化富勒烯等）通过共价连接或物理共混两种方式构建了复合材料体系，利用飞秒和纳秒时域Z-scan技术分析了其非线性特性，明确了复合材料在不同时域、不同波长的脉冲作用下的非线性机理。（4）发展了基于光雕技术的氧化石墨烯图案化还原技术，还原后的氧化石墨烯的碳氧比和导电性显著提高。拓展研究内容如下：（1）针对热致非线性折射，我们提出了基于激光背向散射干涉的光热效应的检测技术；（2）针对化合物吸收光谱的测量，我们提出了基于智能设备的吸收光谱新型分析技术，可用于溶液吸收光谱及浓度的快速、便捷检测。