Y. Harima et al., DRIFT MOBILITY OF HOLES IN VACUUM-DEPOSITED FILMS OF ZINC TETRAPHENYLPORPHYRIN, Chemical physics letters, 258(1-2), 1996, pp. 213-216
Drift mobilities (mu) of holes in zinc tetraphenylporphyrin (ZnTPP) fi
lms were measured using the time-of-flight method. The plot of log mu
vs. a square root of electric field (E(1/2)) fit a straight line and i
ts extrapolation to E=O yielded an extremely small mu value of the ord
er 10(-10) cm(2) V-1 s(-1) at 20 degrees C. The field dependencies of
the hole mobilities at different temperatures were analyzed on the bas
is of the disorder formalism developed by Bassler and co-workers. As a
result, the slow hole transport in the ZnTPP films was ascribed to a
greater energetic disorder parameter(sigma=0.15 eV) resulting from a n
early amorphous structure of the ZnTPP films.