Journal article

Publication year: 2015

Pages: 1147-1158

Journal: Journal of Porphyrins and Phthalocyanines

Volume number: 19

Issue number: 11

ISSN: 1088-4246

eISSN: 1099-1409

DOI Link: https://doi.org/10.1142/S1088424615500923

Publisher: World Scientific Publishing

Abstract: 
Porphyrin nanorods (PNR) have been fabricated by electrostatic self-assembly of two oppositely charged porphyrin molecules. The free base meso-tetra-(4-phenylsulphonate) porphyrin (TPPS 4) served as negatively charged counterpart for the positively charged metallo meso-tetra(4-N-methylpyridyl) porphyrins (MTM'PyP) with either Sn, Co, Mn or In as central metal M. Films of PNR were prepared on fluorine doped tin oxide glass sheets (FTO) by using a drop-dry method. The electronic spectra revealed J-aggregation of the charged molecules for the colloid PNR as well as for the films. Transmission electron microscopy confirmed the formation of porphyrin nanorods. The laser microscope and scanning electron microscope (SEM) images of the PNR/FTO films showed the formation of three kinds of structures in the films which consist of differently branched or linear needles with their main axis grown in the direction of the solvent flow during preparation. During cyclic voltammetry either applying negative potentials from 0.0 V to -1.0 V or positive potentials from 0.0 V to + 2.2 V irreversible reduction or oxidation reactions were detected for the films. Consistently, SEM images taken following cyclic voltammetry showed the disintegration of the PNR on the films into smaller subunits. Spectroelectrochemical measurements showed the formation of porphyrin anionic radicals during oxidation by a decrease in the absorption intensities and broadening of spectra with an additional band appearing around 900 nm. A similar trend was observed when negative potentials were applied but in this case the cationic radical was produced. In both cases the decrease of the intensity of the J-aggregate confirms a loss of intermolecular coupling, again consistent with the smaller subunits observed in SEM analysis.

Harvard Citation style: George, R., Falgenhauer, J., Geis, C., Nyokong, T. and Schlettwein, D. (2015) Characterization of porphyrin nanorods on fluorine doped tin oxide glass sheets, Journal of Porphyrins and Phthalocyanines, 19(11), pp. 1147-1158. https://doi.org/10.1142/S1088424615500923

APA Citation style: George, R., Falgenhauer, J., Geis, C., Nyokong, T., & Schlettwein, D. (2015). Characterization of porphyrin nanorods on fluorine doped tin oxide glass sheets. Journal of Porphyrins and Phthalocyanines. 19(11), 1147-1158. https://doi.org/10.1142/S1088424615500923