Ultrafast carrier phonon dynamics in NaOH-reacted graphite oxide film

• Main Authors: Lee, Dongwook, Zou, Xingquan, Zhu, Xi, Bondino, Federica, Magnano, Elena, Su, Haibin, Seo, J. W., Cole, Jacqueline M., Nair, Saritha K.
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Online Access: https://hdl.handle.net/10356/94514; http://hdl.handle.net/10220/9395
• Institution: Nanyang Technological University

NaOH-reacted graphite oxide film was prepared by decomposing epoxy groups in graphite oxide into hydroxyl and -ONa groups with NaOH solution. Ultrafast carrier dynamics of the sample were studied by time-resolved transient differential reflection (ΔR/R). The data show two exponential relaxation processes. The slow relaxation process (∼2ps) is ascribed to low energy acoustic phonon mediated scattering. The electron-phonon coupling and first-principles calculation results demonstrate that -OH and -ONa groups in the sample are strongly coupled. Thus, we attribute the fast relaxation process (∼0.17ps) to the coupling of hydroxyl and -ONa groups in the sample.