9 July 2007 Fluorescence from upper excited states of porphyrins with one- and two-photon excitation
Author Affiliations +
In this paper we report on the study of S2→S0 blue fluorescence and two-photon absorption (TPA) for a series of Zn-tetrabenzoporphyrins (Zn-TBP) with sequential substitution of phenyl groups in meso-positions. The blue fluorescence has been measured with both one- and two-photon excitation. The data on TPA showed that lowest g-parity state lies above B-state for all these compounds and blue fluorescence has been detected upon two-photon excitagtion at gg transition energies above that of Soret band. The data are in line with the suggested role of the g-parity low-lying state in the nonradiative deactivation of B state. More than two-fold decrease in the relative yield of blue fluorescence was found in going from Zn-monophenyl-TBP to Zn-tetraphenyl-TBP. The enhancement of the radiationless internal S2→S1 and S1→S0 conversion and the decrease in the quantum yield of blue fluorescence was proposed to explain by nonplanar distortions of tetrapyrrolic macrocycle in Zn-tetraphenyl-TBP. The obtained results indicate that the positioning of g-parity excited states above B states is a requirement but not the sufficient condition for presence of blue fluorescence.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
M. Kruk, M. Drobizhev, A. Karotki, A. Rebane, "Fluorescence from upper excited states of porphyrins with one- and two-photon excitation", Proc. SPIE 6727, ICONO 2007: Nonlinear Laser Spectroscopy and High-Precision Measurements; and Fundamentals of Laser Chemistry and Biophotonics, 67272F (9 July 2007); doi: 10.1117/12.752487; https://doi.org/10.1117/12.752487

Back to Top