High rectification in metal-phthalocyanine based single layer devices

The current-voltage (JV) characteristics of metal-phthalocyanine (Me-Pc) ba sed single layer hole only indium tin oxide (ITO)/Me-Pc/Metal devices are i nvestigated. It is demonstrated that diode-like asymmetric J-V characeristi cs with high rectification ratio of about 10(6) can be achieved if an elect rode with low work function is used. But, an electrode with high work funct ion, comparable to the ionization potential of Me-Pc, results in negligible rectification. The J-V characteristics in the forward direction, when ITO is positively biased, can be consistently described as bulk limited space c harge current modified with field dependent mobility. The J-V characteristi cs in the reverse direction, when ITO is negatively biased, are described a s tunneling due to hole blocking barrier at Metal/Me-Pe interface.