Charge-Induced Structure Variations of 1D-Iodine Inside Thin SWCNTs

We present results on the charge-induced transformation of linear 1D-iodine structures encapsulated inside single-walled carbon nanotubes (SWCNTs) with a diameter of about 1 nm. A supercapacitor-type electrochemical cell was developed for the controlled charging of iodide-filled nanotube electrodes. In situ Raman study confirms the change of anion types that are composed of the one-dimensional iodine structures formed inside the SWCNTs. Electronic doping of the iodine@SWCNT system leads to rapid growth of the Raman mode of I-3(-) anions and suppression of the mode of the lower-charged I-5(-) anions. On the other hand, doping with holes leads to a gradual suppression of the I-3(-) mode and then the I-5(-) mode. UV-visible in situ measurements confirm iodine@SWCNT doping.