TY - JOUR
T1 - Preparation and photophysical and photoelectrochemical properties of a covalently fixed porphyrin-chemically converted graphene composite
AU - Umeyama, Tomokazu
AU - Mihara, Junya
AU - Tezuka, Noriyasu
AU - Matano, Yoshihiro
AU - Stranius, Kati
AU - Chukharev, Vladimir
AU - Tkachenko, Nikolai V.
AU - Lemmetyinen, Helge
AU - Noda, Kei
AU - Matsushige, Kazumi
AU - Shishido, Tetsuya
AU - Liu, Zheng
AU - Hirose-Takai, Kaori
AU - Suenaga, Kazu
AU - Imahori, Hiroshi
PY - 2012/4/2
Y1 - 2012/4/2
N2 - Chemically converted graphene (CCG) covalently linked with porphyrins has been prepared by a Suzuki coupling reaction between iodophenyl-functionalized CCG and porphyrin boronic ester. The covalently linked CCG-porphyrin composite was designed to possess a short, rigid phenylene spacer between the porphyrin and the CCG. The composite material formed stable dispersions in DMF and the structure was characterized by spectroscopic, thermal, and microscopic measurements. In steady-state photoluminescence spectra, the emission from the porphyrin linked to the CCG was quenched strongly relative to that of the porphyrin reference. Fluorescence lifetime and femtosecond transient absorption measurements of the porphyrin-linked CCG revealed a short-lived porphyrin singlet excited state (38 ps) without yielding the porphyrin radical cation, thereby substantiating the occurrence of energy transfer from the porphyrin excited state to the CCG and subsequent rapid decay of the CCG excited state to the ground state. Consistently, the photocurrent action spectrum of a photoelectrochemical device with a SnO 2 electrode coated with the porphyrin-linked CCG exhibited no photocurrent response from the porphyrin absorption. The results obtained here provide deep insight into the interaction between graphenes and π-conjugated systems in the excited and ground states.
AB - Chemically converted graphene (CCG) covalently linked with porphyrins has been prepared by a Suzuki coupling reaction between iodophenyl-functionalized CCG and porphyrin boronic ester. The covalently linked CCG-porphyrin composite was designed to possess a short, rigid phenylene spacer between the porphyrin and the CCG. The composite material formed stable dispersions in DMF and the structure was characterized by spectroscopic, thermal, and microscopic measurements. In steady-state photoluminescence spectra, the emission from the porphyrin linked to the CCG was quenched strongly relative to that of the porphyrin reference. Fluorescence lifetime and femtosecond transient absorption measurements of the porphyrin-linked CCG revealed a short-lived porphyrin singlet excited state (38 ps) without yielding the porphyrin radical cation, thereby substantiating the occurrence of energy transfer from the porphyrin excited state to the CCG and subsequent rapid decay of the CCG excited state to the ground state. Consistently, the photocurrent action spectrum of a photoelectrochemical device with a SnO 2 electrode coated with the porphyrin-linked CCG exhibited no photocurrent response from the porphyrin absorption. The results obtained here provide deep insight into the interaction between graphenes and π-conjugated systems in the excited and ground states.
KW - energy transfer
KW - graphene
KW - photophysics
KW - porphyrinoids
KW - time-resolved spectroscopy
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U2 - 10.1002/chem.201103843
DO - 10.1002/chem.201103843
M3 - Article
C2 - 22374704
AN - SCOPUS:84859323543
VL - 18
SP - 4250
EP - 4257
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 14
ER -