ABSTRACT
Polyimides(PI)havebeenwidelyusedasanelectricalinsulatingmaterialin electronicsandelectricalengineering,becauseoftheirexcellentheatresistance properties,chemicalstabilityandmechanicalproperties.Manyinvestigationshave beencarriedoutinthefieldsofchemistry,photonicsandelectronics[1,2].Wehave beenstudyingtheelectronicpropertiesofultra-thinPIfilmssincethesuccessful preparationofPILangmuir-Blodgett(LB)filmsbytheprecursormethod[3]. UsingtheKelvinprobemethodforsurfacepotentialmeasurements,nano-interfacial electrostaticphenomenaatthePIfilm-metalinterfacehavebeenclarified.An electrostaticpotentialwasbuiltatthePIfilm-metalinterfaceduetotheexcess chargetransferfromthemetaltothefilmwithinaregionofapprox.10nmfrom theinterface.Thisinterfacialspacechargedensitywasquitehigh(IOS-106C/m3) attheinterface,butitrapidlydecreasedasthedistancefromthemetalelectrode increased[4].Thesefindingsontheinterfacialelectrostaticpropertieswouldbe veryhelpfulforabetterunderstandingoftheperformanceoforganicthin-film devices,suchasorganicelectro-luminescentdevices(OELs),organicfield-effect
transistors (OFETs), etc. [5, 6]. In these devices the influence of the interfacial space charge on electron transport becomes more evident as the film thickness decreases, e.g., to 1-10 nm [7].
