Ultrafast vibrational dynamics affected by xylyl functionalization of carbon nanotube

Atsushi Yabushita^1,2*, Yutaka Maeda³, Masahiro Ehara⁴, Takayoshi Kobayashi¹

¹Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Research Institute of Engineering, Kanagawa University, Kanagawa, Japan
³Department of Chemistry, Tokyo Gakugei University, Tokyo, Japan
⁴Research Center for Computational Science, Institute of Molecular Science, Okazaki, Japan

* Presenter:Atsushi Yabushita, email:yabushita@nycu.edu.tw

Chemical functionalization of carbon nanotube by xylyl group has been reported to improve emission yield with large red-shift of emission wavelengh. The intense near infrared emission is thought to be useful for various applications including bioimaging which prefer longer emission wavelength for less scattering loss in thick biological tissue. The mechanism which causes the intense NIR emission is still unknown which is needed to be clarified for development with better performance. In the present work, we have performed ultrafast transient absorption spectroscopy using 10-fs ultrashort visible broadband laser to study difference of utlrafast dynamics for xylyl functionalized one and non-functionalized one. The result has shown that the electronic dynamcis are comparable between the two samples but difference was found in a molecular vibrational mode dynamics of graphene mode. With support of quantum chemical calculation, it was elucidated that ultrafast intramolecular vibrational energy redistribution proceeds only in xylyl functionalized sample.

Keywords: ultrafast spectroscopy, carbon nanotube, ultrashort laser pulse, molecular vibration dynamics