Solution-processed nickel tetrabenzoporphyrin thin-film transistors

We describe nickel tetrabenzoporphyrin (NiTBP) as a solution-processible organic semiconductor. Whereas porphyrins in an unmodified state are typically planar and insoluble, a precursor synthetic route (NiCP) was used to deposit thin films via solution. Amorphous, insulating thin films of NiCP were deposited, and thermally converted to polycrystalline, semiconducting NiTBP. Films were studied using optical absorption and microscopy, atomic force microscopy, and x-ray diffraction. Highly concentrated NiCP was shown to form large, needle-shaped crystals drop-cast from solution. NiTBP thin-film field-effect transistors fabricated from spun-cast films demonstrated charge-carrier field-effect mobilities on the order of 0.1 and 0.2 cm(2)/V s and accumulation threshold voltages of -19 and -13, in the linear and saturation regimes, respectively. (c) 2006 American Institute of Physics.