TRANSIENT PHOTOINDUCED VOLTAGE IN HETERO-STRUCTURED POLYIMIDE LANGMUIR-BLODGETT-FILMS

We developed a transient photoinduced voltage measuring system and the n investigated the photoinduced electron transfer in heterostructured polyimide Langmuir-Blodgett films consisting of a polyimide of one typ e (PI) and a polyimide of another type containing a tetraphenylporphyr in moiety (PORPI). The photoinduced transient voltage depended on the PORPI layers (n), indicating that there are two kinds of electron tran sfer mechanism. For n exceeding 3, the maximum value of the induced tr ansient voltage increases with n. We conclude that photoexcited electr ons were transported in PORPI films at a distance of 2-4 nm.