Comparative analysis of metal diffusion effects in polymer films coated with spin coating and floating film transfer techniques

[Display omitted] •Effect of gold diffusion in rr-P3HT Spin-coated (SC) and Floating Film Transfer Method (FTM) coated thin films.•Higher morphological disruption was observed in FTM films upon gold(Au) coating.•Larger barrier at Au/FTM P3HT interface corroborated to larger diffusion of Au atoms in these devices.•The results are critical for fabrication of top contact devices involving FTM films as active layer. In this work a comparative analysis between the extent of gold diffusion of the top coated gold layer into the conducting polymer matrix of spin coated polymer films and polymer films coated via floating film transfer method (FTM) has been investigated. For the sake of comparison two different device configurations i.e. ITO/rr-P3HT (spin coated)/Au and ITO/rr-P3HT (spin coated)/rr-P3HT (FTM coated)/Au have been compared. The J-V characteristics of these devices revealed a non-Ohmic injection occurring near the top gold electrode/polymer interface. Furthermore, the current flowing through the device consisting of FTM layer/Au interface was observed to be lower as compared to the one consisting of spin coated layer/Au interface, indicating higher gold diffusion in well-ordered FTM thin films. These observations have been validated by optical and structural characterization methods viz. absorption, photoluminescence, Raman spectroscopy and X-Ray Diffraction (XRD) measurement. Finally Fowler-Nordheim (FN) tunneling currents were studied under high electric field applications for the two devices which confirmed presence of higher barrier at the interface of gold and FTM coated polymer film.