Search

Ahmed Abouelsayed
Pressure eff%1Bect on Single-walled and Double-walled Carbon Nanotubes Investigated by Infrared Spectroscopy
Supervisor: Prof. Dr. Christine Kuntscher [Experimental physics II]
Date of oral examination: 10/11/2012
125 pages, english
We present a systematic study of pressure effects in various CNTs samples: SWCNTs (unoriented and oriented), C60 peapods and DWCNTs films in the NIR-Visible frequency range for using different pressure transmitting medium for pressures up to 9 GPa. In all films (unoriented and oriented SWCNTs, C60 Peapods and DWCNTs) the optical transitions shift to lower energies with increasing pressure. The amount of this red-shift is comparable in SWCNTs (unoriented and oriented) and C60 peapods films for using different pressure transmitting medium. For DWCNTs films, the red-shift is much smaller for using alcohol mixture as a pressure medium, and increases in case of argon and CsI. The pressure dependence of the optical transitions exhibits an anomaly at about 2-3 GPa, and second anomaly around 6 GPa for SWCNTs (unoriented nanotube films and the nanotubes-polymer matrix) for using different pressure media. In the case C60 peapods, the first anomaly is observed around 3 GPa and second anomaly is observed around 5 GPa for using alcohol mixture as a pressure transmitting medium, while the first anomaly is observed around 1.5 GPa and 2 GPa in the case of using CsI and argon respectively. The second anomaly is not observed in the case of using argon and CsI as a pressure transmitting media. There is no clear observed anomaly in the case of DWCNTs film.