Enhancement in the dark conductivity of benzoylferrocene upon adsorpti
on of different organic vapors has been studied with the help of sandw
ich cell technique. Plot of dark conductivity vs temperature shows con
ductivity peak(s). The position of the peaks as well as the intensity
have been found to depend on the amount as well as the nature of adsor
bed vapor. In presence of adsorbed vapors, this material shows a very
high value of activation energy (E) and the pre-exponential factor (si
gma0) in the usual semiconduction equation [sigma=sigma0 exp (-E/2kT)]
. Existing theories for adsorption-induced change in the electrical co
nductivity of materials are not suitable for explaining the observed r
esults. Possible reasons for the adsorption-induced changes in the con
ductivity behavior have been discussed.