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High‐Temperature Cs x C 58 Fullerides
Author(s) -
Ulas Seyithan,
Weippert Jürgen,
Malik Sharali,
Strelnikov Dmitry,
Kern Bastian,
Amati Matteo,
Gregoratti Luca,
Kiskinova Maya,
Böttcher Artur
Publication year - 2019
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201800453
Subject(s) - sublimation (psychology) , covalent bond , highly oriented pyrolytic graphite , crystallography , ionic bonding , fullerene , thermal stability , materials science , carbon fibers , pyrolytic carbon , phase (matter) , doping , graphite , scanning tunneling microscope , analytical chemistry (journal) , nanotechnology , chemistry , ion , pyrolysis , organic chemistry , psychology , optoelectronics , composite number , composite material , psychotherapist
Cs doped non‐IPR fullerides (IPR: isolated pentagon rule) have been grown by co‐depositing C 58 cations and Cs atoms on highly oriented pyrolytic graphite (HOPG). The C 58 cages, as building blocks of the material, form a predominantly covalently stabilized scaffold, C 58 –C 58 , which is doped by Cs atoms thermally diffusing across the bulk. The heating of the solid Cs x C 58 sample is accompanied by sublimation of Cs, C 58 , and C 60 species from the topmost layers of the sample. However, the major part (>94%) of the material survives the heating procedure and constitutes a doped high‐temperature carbon solid, HT‐Cs x C 58 . The new non‐IPR material exhibits surprisingly high thermal stability. It survives a heating flash up to 1100 K at which the classic IPR‐Cs x C 60 phase does not exist anymore. However, the thermally treated HT‐Cs x C 58 phase exhibits a considerably depleted Cs content ( x < 2) and a significantly modified carbon scaffold. The apparent stability of the scaffold results from covalent C–C bonds interlinking adjacent carbon cages. Cs atoms in the HT‐Cs x C 58 phase contribute to this stability only as minority species, forming comparably weak ionic bonds with C 58 –C 58 oligomers. However, this interaction facilitates the formation of structural defects (new non‐IPR sites) in carbon cages. The surface topography of the HT‐Cs x C 58 as monitored by scanning photoemission microscopy, atomic force microscopy, and scanning electron microscopy is governed by islands standing out by their elevated Cs/C ratio.