TY - JOUR
T1 - Time-resolved infrared vibrational spectroscopy of the photoinduced phase transition of Pd(dmit)2 salts having different orders of phase transition
AU - Fukazawa, Naoto
AU - Tanaka, Takahiro
AU - Ishikawa, Tadahiko
AU - Okimoto, Yoichi
AU - Koshihara, Shin Ya
AU - Yamamoto, Takashi
AU - Tamura, Masafumi
AU - Kato, Reizo
AU - Onda, Ken
N1 - Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013/6/27
Y1 - 2013/6/27
N2 - To clarify the mechanism of the later process of photoinduced phase transition (PIPT) in organic charge-transfer complexes, we examined by time-resolved infrared vibrational spectroscopy two dimeric anion radical salts, Et2Me2Sb[Pd(dmit)2]2 (Et 2Me2Sb salt) and Cs[Pd(dmit)2]2 (Cs salt) (Et, Me, and dmit are C2H5, CH3, and 1,3-dithiol-2-thione-4,5-dithiolate, respectively), having similar characteristics except for the order of their phase transitions at thermal equilibrium. The phase transition is first order for the Et2Me 2Sb salt and second order for the Cs salt at thermal equilibrium. Although both salts exhibit a high-temperature phase at later delay times (>100 ps) after the photoexcitation of the low-temperature phase, the time required for the emergence of the high-temperature phase was significantly different: 70 ps for the Et2Me2Sb salt and <0.1 ps for the Cs salt. The slow emergence of the high-temperature phase in the PIPT of the Et2Me2Sb salt presumably has an origin similar to that recognized for the first-order thermal phase transition, that is, steric effects of the Et2Me2Sb cation when the phase transitions occur.
AB - To clarify the mechanism of the later process of photoinduced phase transition (PIPT) in organic charge-transfer complexes, we examined by time-resolved infrared vibrational spectroscopy two dimeric anion radical salts, Et2Me2Sb[Pd(dmit)2]2 (Et 2Me2Sb salt) and Cs[Pd(dmit)2]2 (Cs salt) (Et, Me, and dmit are C2H5, CH3, and 1,3-dithiol-2-thione-4,5-dithiolate, respectively), having similar characteristics except for the order of their phase transitions at thermal equilibrium. The phase transition is first order for the Et2Me 2Sb salt and second order for the Cs salt at thermal equilibrium. Although both salts exhibit a high-temperature phase at later delay times (>100 ps) after the photoexcitation of the low-temperature phase, the time required for the emergence of the high-temperature phase was significantly different: 70 ps for the Et2Me2Sb salt and <0.1 ps for the Cs salt. The slow emergence of the high-temperature phase in the PIPT of the Et2Me2Sb salt presumably has an origin similar to that recognized for the first-order thermal phase transition, that is, steric effects of the Et2Me2Sb cation when the phase transitions occur.
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U2 - 10.1021/jp403193a
DO - 10.1021/jp403193a
M3 - Article
AN - SCOPUS:84879647642
VL - 117
SP - 13187
EP - 13196
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 25
ER -