Electronic density of state at metal/polyimide Langmuir-Blodgett film interface

Surface potentials of heat-treated polyimide (PI) LB films deposited on Au, Cr and Al electrodes were measured in a dark vacuum vessel at various temperatures as a function of the number of deposited layers. The spatial charge distribution in PI LB films on various electrodes was determined from the relationship between the surface potential and the number of deposited layers. Based on this result, distribution of the density of electronic state in PI LB films was determined. It was experimentally shown that the charge exchange phenomena in PI LB films at the metal/film interface were explained with taking account of interfacial states which exist within the range of 1 nm from the interface and molecular-ion states which exist in the entire range. Further, it was found that the distribution of electronic density of states in polyimides was broadened as the temperature increases