H. Monobe et al., Photoconductive properties of a mesogenic long-chain tetraphenylporphyrin oxovanadium(IV) complex, THIN SOL FI, 393(1-2), 2001, pp. 217-224
The photoconductive properties of a mesogenic long-chain tetraphenylporphyr
in, 5,10,15,20-tetrakis(4-n-pentadecylphenyl)porphinatooxovanadium(IV) were
investigated and compared with those of the metal-free compound for a symm
etrical sandwich-type ITO cell. This compound shows two types of lamellar m
esophases (M-LC and M-L phases) and the phase transition sequence is Cr 51
M-LC 83 M-L 140 Iso. A similar photocurrent rectification behavior to the c
orresponding metal-free tetraphenylporphyrin mesogen was shown. However, th
e observed photocurrent was remarkably larger than that of the metal-free c
ompound for all phases. The action spectra and the temperature dependence o
f the dark- and photocurrents were also investigated on the mesomorphic pha
se transition behavior. These results imply that the photoconductive proper
ty of mesogenic tetraphenylporphyrin-based compounds could be drastically a
ffected by a change of molecular fluctuation and long-range order through m
esomorphic phase transitions and a metal species inserted in the central co
re. (C) 2001 Elsevier Science B.V. All rights reserved.