Solution Processable Transition Metal Phthalocyanine Nanofibres

Abstract

Solution processable organic functional materials are highly desirable for device fabrication and applications. The insoluble nature of unsubstituted metal phthalocyanines (MPcs) often limits their applications that demand solution based coating techniques. In this work, nano‐architectures of metal phthalocyanines with important transition metal ions, Mn, Fe, Co, Cu and Zn that are highly dispersible in polar organic solvents have been prepared through a simple chemical route and applied as electrode materials for electrochemical hydrogen evolution reaction (HER). The formation of different MPcs is confirmed through various techniques such as Raman spectrocopy, X‐ray diffraction and X‐ray photoelectron spectroscopy. The morphology of the synthesized MPcs has a fibre‐like structure with varying dimensions of 150–650 nm in width and 5–10 μm in length. These nanostructures are supramolecular self‐assemblies of individual macrocycle rings coming together to form fibre‐like structures through π‐π interactions and are highly ordered with β crystal phase. The obtained CuPc and CoPc nanofibre dispersion coated on to a glassy carbon electrode exhibited an onset potential of −250 and −290 mV and a Tafel slope of 120 and 107 mV dec−1, respectively, for HER and good stability up to 1000 cycles.

Molecular origin of structural defects in the zinc phthalocyanine film

“…Alternatively MPcs can be processed into thin films from solutions. 10 The solution-processing technique is best applicable to ZnPc, which can be readily solubilized in non-toxic solvents using amino alcohols that also promote the uniform deposition of dye crystallites. 11 However, to transform the island-like film morphology 12 into the optimal layer-plus-island morphology, 13 deeper insights into the film structure must be achieved.…”