P. Bassoul et al., SEMICONDUCTIVITY AND GAS-SENSING PROPERTIES OF CROWN-ETHER-SUBSTITUTED LUTETIUM BISPHTHALOCYANINES, Sensors and actuators. B, Chemical, 26(1-3), 1995, pp. 150-152
The conductivity of thin films of crown ether (15-crown-5, 18-crown-6)
substituted lutetium bisphthalocyanines has been studied in the prese
nce of various gases. Under vacuum the films show intrinsic semiconduc
ting properties (sigma approximate to 10(-6) Omega(-1) cm(-1)). When e
xposed to an oxidant (O-2, I-2, Br-2), the molecular semiconductors ar
e progressively transformed into doped insulators (sigma approximate t
o 10(-9) Omega(-1) cm(-1)). Exposure to wet nitrogen yields fully reve
rsible conductivity changes: a two orders of magnitude difference in c
onductivity is measured on oxidized films when the relative humidity v
aries from 10% to 90%.