Nanometric electrostatic interfacial phenomena in organic semiconducting thin films

Surface potentials of two kinds of phthalocyanine Langmuir-Blodgett (LB) fi lms deposited on metal electrodes were examined as a function of the number of deposited layers. It was found that the potential built across the LB f ilms was due to the displacement of excessive electronic charges (electrons and holes) from metals. The spatial charge distribution in these LB films was determined to be of the order of nanometres in film thickness, and the distribution of the electronic density of states was also determined assumi ng the presence of both electron donating and accepting states at the metal /film interface. The capacitance-voltage (C-V) and current-voltage (I-V) ch aracteristics of phthalocyanine LB films sandwiched between metal electrode s were examined taking into account the interfacial electrostatic phenomena .