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The kinetics of the solid-state conversion and crystallization of metal tetrabicycloporphyrins (M-CPs) to metal tetrabenzoporphyrins complexes (M-TBPs) were analyzed by using the Avrami-type equation, and the value of the indices (n) was found to depend on the central atom in M-CP: n = 3 for M = H (TBP), n = 2 for M = Zn, and n = 3 at low temperatures and n = 2 at high temperatures for M = Ni. The heat of crystallization was similar for the M-TBPs, but the activation energy of crystallization varied with the type of central atom. For Ni-TBP and Zn-TBP, metastable phases were first forms, which were then converted into a stable phase, while no such metastable phase was formed in the case of TBP. In addition, the crystallization behavior of TBP was different from that in the thin film state (reported previous study). The crystallization onset temperature varied with the heating rate, although the true temperatures obtained by extrapolating the different heating rates data to zero heating rate were the same. Finally, from the PXRD data, the crystal grains of M-TBPs were found to grow isotropically in the three different directions.

A small molecule organic semiconductor CuTBP (copper tetrabenzoporphyrin) was formed from a precursor CuCP (Copper tetrabicycloporphyrin) using a solution process. In this study, the solid-state crystallization process of CuTBP on a substrate surface was observed and evaluated. To obtain good semiconductor performance, it is very important to understand and control the crystallization process, which was found to consist of three steps during annealing. These steps were clearly observed with XRD-DSC. Although the starting temperatures of the first and second CuTBP crystallization steps did not show distinct changes, the starting temperature of the third step changed significantly with the heating rate, requiring a temperature higher than 145°C. The grain morphology also changed depending on the crystallization temperature. At lower crystallization temperatures, the growth of homogeneously colored grains having diamond shapes was promoted, while at higher temperatures heterogeneously colored grains of petal shapes were formed.