Excited-state dynamics of meso-tetrakis(sulfonatophenyl) porphyrin J-aggregates

The excited-state dynamics of free-base meso-tetrakis(sulfonatophenyl) porphyrin J-aggregates obtained by the Z-scan technique in femto- and picosecond time scales, along with UV–Vis spectroscopy and flash photolysis is reported. Besides obtaining the S1 state lifetime, the discrimination between internal conversion and intersystem crossing nonradiative processes from that state was also possible, and their rates and respective quantum yields were found. The aggregates present reverse saturable absorption at 532 nm for both singlet and triplet excited states. The data shown is important for several applications such as optical limiting, photodynamic therapy and others.

► Excited-state dynamics of porphyrin J-aggregates. ► Cross-sections, S1 state lifetime, rates and quantum yields. ► Discrimination between internal conversion and intersystem crossing nonradiative processes.