还原氧化石墨烯光学非线性

Optical Nonlinearities of Reduced Graphene Oxide

利用飞秒激光抽运-探测和Z扫描技术研究了氧化石墨烯和在不同还原时间下的氧化石墨烯的超快动力学过程及非线性吸收性质。将氧化石墨烯用肼蒸汽还原,通过控制还原时间,得到不同的还原氧化石墨烯材料。通过X射线光电子光谱实验测试了材料的含氧量和不同官能团含量。抽运-探测实验结果显示还原后石墨烯载流子衰减速度明显加快,各官能团的含量也会影响载流子的衰减过程。Z扫描实验结果显示还原后样品的饱和吸收明显增强。对氧化石墨烯还原后,再延长还原时间并不能明显改变还原氧化石墨烯的饱和吸收性质,这种变化同还原氧化石墨烯的结构变化相关。

The ultrafast carrier dynamics and nonlinear optical properties in graphene oxide and reduced graphene oxide of different reduced time are investigated using pump-probe and Z-scan techniques with femtosecond laser pulses. Partially reduced graphene oxides are produced by expositing graphene oxide to the hydrazine vapor for different time. The extent of oxidation and contents of different functional groups in materials aremeasured by X-ray photoelectron spectroscopy. Results of pump-probe experiments show that the decay time of carrier relaxation of graphene oxide become shorter after being reduced. The amount of functional groups also affects the ultrafast dynamics process in reduced graphene oxide. For nonlinear optical properties, experiments of Z-scan results show that the saturable absorption property of graphene oxide is enhanced after being reduced. After reduction for a certain time, the enhancement of saturable absorption will not be changed visibly. It is greatly related to the extent of reduction.