Investigation of molecular orientation in thin films of polythiophenes fabricated on air-liquid interface

摘要

Performance and operational lifetime of organic material based electronic and optoelectronic devices depend on the degree of electron delocalization and its stability. Apart from material properties, another challenge in exploiting the potential of organic electronics is its cost, user-friendly, and ordered/crystalline thin film fabrication techniques. Therefore, a facile deposition technique is highly desired to have precise control over polymer chain ordering along with large area homogeneous thin film fabrication. In this work, the floating-film transfer method (FTM) has been utilized, which provides a large area, highly oriented, crystalline, and smooth polymer thin films. In the case of self-assembled conjugated polymer thin films, the edge of the crystalline domains corresponds to the folded polymeric chains. These folding introduces constraints in the growth of crystalline domains by limiting the successive molecular chain packing as well as causes lattice parameter fluctuation. Therefore, local alignment of polymeric chains in close proximity via-stacking can counterbalance disorders like backbone twisting, chain ends, stacking faults, etc. This work provides a novel technique to fabricate highly edge-on oriented thin solid films of polythiophene and its derivatives.