| Numéro |
J. Phys. IV France
Volume 114, April 2004
|
|
|---|---|---|
| Page(s) | 553 - 555 | |
| DOI | https://doi.org/10.1051/jp4:2004114131 | |
J. Phys. IV France 114 (2004) 553
DOI: 10.1051/jp4:2004114131
Molecular conductors containing photoreactive species
T. Naito1, 1, 2, 1, 3, 1 and T. Inabe21 Division of Innovative Research, Creative Research Initiative "Sousei" (CRIS), Hokkaido University, Kita 20, Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan
2 Division of Chemistry, Graduate School of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
3 Department of Molecular Assemblies, Institute for Molecular Science (IMS), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
Abstract
In order to examine the possibility of (persistent)
carrier doping to molecular crystals by light exposure, some different types
of molecular crystals containing photoreactive species are synthesized and
characterized. The [ Ru(bpy)
3]
2+ cation (bpy = 2,2'-bipyridyl)
yielded two different new complexes with [ Ni(dmit)
2]
- radical
species, both of which were structurally characterized and turned out to be
band insulators. Methy viologen (MV) has been found to yield a new phase of
the complex with [ Ni(dmit)
2]
-, MV[ Ni(dmit)
2]
2. The
temperature dependences of electrical resistivity (decreasing with lowering
temperature down to 1.0 K) and magnetic susceptibility (Pauli paramagnetism
from 300 K to 1.8 K with a hysteresis below
100 K) clearly indicate
that this phase is metallic. The thermoelectric power exhibited
0
VK
-1 from 300 K-4.2 K. This phase turned out to be metastable,
and the crystals gradually turned into insulating ones. The effects of
UV-VIS light exposure to the conducting and magnetic properties of
Ag(DMe-DCNQI)
2 have been studied, and clear differences between the
exposed and the pristine crystals were observed. The ESR signal at 3.7 K
suggested that the exposed sample should include the Ag(0) species.
Key words. Photoreaction - doping - conductivity.
© EDP Sciences 2004