Polyiodide-Doped Graphene

Abstract

Iodine-doped graphene has recently attracted significant interest as a result of its enhanced conductivity and improved catalytic activity. Using density functional theory calculations, we obtain the formation energy, desorption rate, and electronic properties for graphene systems doped with polyiodide chains consisting of 1–6 iodine atoms in the low-concentration limit. We find that I3 and I5 act as p-type surface dopants that shift the Fermi level 0.46 and 0.57 eV below the Dirac point, respectively. For these two molecules, molecular orbital theory and analysis of the charge density show that doping transfers electronic charge to iodine π* molecular orbitals oriented perpendicular to the graphene sheet. For even-length polyiodides, we find that I6 and I4 decompose to I2, which readily desorbs at 300 K. Adsorption energy calculations further show that I3 acts as an effective catalyst for the oxygen reduction reaction on graphene by stabilizing the rate-limiting OOH intermediate.

Charged iodide in chains behind the highly efficient iodine doping in carbon nanotubes

“…Since the dissociation of a single I 2 on graphene is clearly unfavorable (+0.74 eV) [17], more molecules should be considered. First, we calculated interaction of four iodine atoms inside a SWCNT and between SWCNTs inside a 064002-2 bundle.…”

“…Recent ab initio calculations of graphene doping by iodine suggested that various iodine species should be considered [16,17]. Even though many characterization studies have been conducted on doping processes in CNTs [18][19][20], the mechanism of iodine doping remains a long-debated subject.…”

Pressure‐Induced Polymerization and Electrical Conductivity of a Polyiodide

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We report the high-pressure structural characterization of an organic polyiodide salt in which ap rogressive addition of iodine to triiodide groups occurs.C ompression leads to the initial formation of discrete heptaiodide units, followed by polymerization to a3Danionic network. [2][3][4] Nowadays,v arious PIs are known, ranging from I 3 À to I 29 3À ,with the general formula I nÀ 2 m+n and n up to 4. [1] Their structural diversity,which is due to the bonding flexibility of iodine,r emains the subject of continuous interest.

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Ab Initio Study of Iodine-Doped Carbon Nanotube Conductors

“…In general, the performance of iodine-doped CNT systems may be affected by iodine atom interactions. An example is the presence of iodine in polyiodide form, as described in experimental papers on both CNT [3,49] and graphene [50], which suggest that I À 3 and I À 5 polyiodide chains may be formed during the doping process. An iodine chain structure located inside CNT's was also observed in experiments performed by Fan et al [51].…”