Charge transient, electrochemical and impedance measurements as tools for characterization of nano-heterostructural organic/inorganic semiconductors

Abstract

Some organic small molecules as well as conjugated polymers are attractive organic semiconductors with rich applications in the branch of immerging organic electronics, e.g., in light-emitting, switching and photovoltaic devices. Surprisingly, there is the lack of methods, suitable for elucidation of basic injection and transport properties. This contribution deals with application of several techniques based on charge transient measurements, isothermal charge transient spectroscopy (IQTS) in microscopic mode, electrochemical methods of double step voltcoulometry (DSVCM) and electrochemical impedance spectroscopy (EIS), which are potentially suitable for obtaining information about basic parameters of traps and their influence on the transport properties. To test the characterization methods we first used the prototypical polysilane-poly[methyl(phenyl)silylene] (PMPSi). Phototodegradation of the by UV radiation is known to cause chain scission and creation of dangling bonds and weak bonds by known mechanisms. Next we show the applicability to study the electron structure of presented methods on PPV and blend of PPV and nano-CdS.