Enhanced Optical Nonlinearity of Polyaniline−Porphyrin Nanocomposite

We observe that the porphyrin derivative 4,4′,4′′,4′′′-(porphine-5,10,15,20- tetrayl)tetrakis(benzoic acid) (PTBA) forms nanoparticles when mixed with the electrochemically formed conducting polymer polyaniline (PANI) in a DMF/water mixture. From atomic force microscopy (AFM) studies, the nanoparticles are found to be fairly uniform in size, with a dimension of around 80−100 nm and a z -height of 3−4 nm. The nonlinear optical absorption of this nanocomposite is measured at an excitation wavelength of 532 nm using the open aperture Z-scan experiment. The nanocomposite is found to show an enhanced optical limiting property compared to its constituent compounds PTBA and PANI.