2D positional profiling of orientation and thickness uniformity in the semiconducting polymers thin films

Abstract

Abstract Harnessing the full potential of solution processable conjugated polymers (CPs) as active semiconductor elements lies in the facile thin film fabrication along with amicable control of molecular self-assembly and orientation. Probing the nature and uniformity of thin films are inevitable for fabrication of devices with high reproducibility. Herein, a new method for the fast and facile profiling of thickness and molecular orientation of large area thin films is being reported. Thin films of PBTTT-C14 fabricated by three different methods like floating film transfer method (FTM), friction transfer and spin coating were subjected to profiling of thickness and molecular orientation using 2D positional mapping system followed by fabrication of organic thin film transistors. In order to prove applicability of the mapping system on other CPs, oriented films of PQT-C12 were also prepared by FTM and optical anisotropy estimated by the mapping system (23.0) and conventional spectrophotometer (22.4) validates the performance of our positional mapping system. Spin-coated thin films of PBTTT-C14 subjected to positional profiling of the film uniformity revealed that films are non-uniform and there was a gradual increase in the thickness from center to the periphery.