Formation of new types of porphyrin H- and J-aggregates

A new type of porphyrin H- and J-aggregates was formed by simply mixing aqueous solutions of two kinds of porphyrins with opposite charges, tetrakis(4-sulfonatophenyl)porphyrin cobalt(II) ([CoTPPS]4−) and protonated tetrakis(4-N,N,N-trimethylanilinium)porphyrin ([H4TAPP]6+). Triangular porphyrin aggregates and spherical porphyrin aggregates were observed by TEM. The formation mechanisms of the aggregates are discussed. Optical properties of the aggregates were investigated by UV–vis spectra and fluorescence spectra. The absorption intensity and the emission intensity of the solution placed for 72 h increase a little, which could be caused by the formation of the aggregates with ordered structures in the system. The materials were potential in constructing the functional composite devices to improve the light energy conversion.