Surface pressure induced charge transfer between fullerene and tetrathiafulvalene derivative in Langmuir-Blodgett films.
Structures and electronic states of a 1:1 mixture of bis-tetrathiafulvalene annulated macrocycle (1) and C60 in Langmuir films at the air-water interface and Langmuir-Blodgett (LB) films on solid substrates were examined. Compression of the Langmuir films induced for the first time a phase transition from a weakly interacting state without charge transfer (CT) to a neutral CT state. The scanning force microscope images of LB films transferred onto mica by a single withdrawal showed quite different spatial patterns depending on the CT states. When deposited at around 1 mNm(-1), a domain structure with 3 nm height was obtained, which corresponded to the state without CT interaction. Contrastingly, once the CT interaction was induced by applying surface pressure, a network structure was observed with a height of 6 nm. The CT band, whose transition moment was almost parallel to the substrate surface, was observed at 11.5 x 10(3) cm(-1) in the polarized UV-VIS-NIR spectra of the films deposited at 9 mNm(-1). The phase transition was irreversible, although the surface pressure-area isotherm showed a reversible behavior below 9 mNm(-1). The morphology and electronic state of the film was controllable merely by changing the surface pressure at the air-water interface.
Nakamura
Takayoshi
T
Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan.
Miyata
Hideto
H
Wakahara
Keisuke
K
Akutagawa
Tomoyuki
T
Hasegawa
Tatsuo
T
Hasegawa
Hiroyuki
H
Mashiko
Shinro
S
Christensen
Christian A
CA
Becher
Jan
J
D004563:Electrochemistry; D037741:Fullerenes / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D011312:Pressure; D013053:Spectrophotometry; D013499:Surface Properties
D037741:Fullerenes; D006571:Heterocyclic Compounds; D047028:Macrocyclic Compounds; C063887:tetrathiafulvalene