title: Switchable semiconductive property of the polyhydroxylated metallofullerene.
abstract: The temperature-sensitive property of polyhydroxylated metallofullerene film of Gd@C82(OH)x with special hydroxyl number was studied using synchrotron radiation ultraviolet photoelectron spectroscopy (UPS) and TEM techniques. From room temperature (RT) to 4 degrees C the photoelectron onset energy of the spectra of Gd@C82(OH)12 shifted from 1.9 to 0.2 eV, indicating that Gd@C82(OH)12 automatically shifted from insulator at RT to semiconductor at 4 degrees C. However, this could not be observed for Gd@C82(OH)20. TEM experiments show that the variation of conductivity can be ascribed to formation of a microcrystal under low temperature. The dipole moment induced unique intermolecular interactions and self-assembled microcrystalline structures for Gd@C82(OH)12. This may cause reconstruction of the upper valence band formed by pi-like electrons as well as the density of states (DOS) around the Fermi level (EF) and reconstruct the deeper valence band formed by sigma-like electrons, eventually resulting in a shift to a semiconducting nature. These findings revealed a novel nature for polyhydroxylated Gd@C82(OH)x materials: Their insulating properties can be controllably tuned into semiconducting ones as a function of temperature.
authors: Lab for Bio-Environmental Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China.
authors: Jun
authors: J
authors: Tang
authors: Gengmei
authors: G
authors: Xing
authors: Yuliang
authors: Y
authors: Zhao
authors: Long
authors: L
authors: Jing
authors: Hui
authors: H
authors: Yuan
authors: Feng
authors: F
authors: Zhao
authors: Xueyun
authors: X
authors: Gao
authors: Haijie
authors: H
authors: Qian
authors: Run
authors: R
authors: Su
authors: Kurash
authors: K
authors: Ibrahim
authors: Weiguo
authors: W
authors: Chu
authors: Lina
authors: L
authors: Zhang
authors: Katsumi
authors: K
authors: Tanigaki
mesh_terms: D004553:Electric Conductivity; D004583:Electrons; D037741:Fullerenes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010777:Photochemistry; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D037741:Fullerenes; D014867:Water; D006046:Gold