Nonlinear absorption properties of 5,10-A2B2 porphyrins - correlation of molecular structure with the nonlinear responses.
Citation:Zawadzka M, Wang J, Blau WJ, Senge MO, Nonlinear absorption properties of 5,10-A2B2 porphyrins - correlation of molecular structure with the nonlinear responses., Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology, 12, 2013, 996 1007
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The nonlinear absorption properties of two series of novel free base and metalated meso 5,10-A 2 B 2 sub- stituted porphyrins, both bearing p -tolyl as an A substituent and TMS-ethynyl or bromine as a B substitu- ent, were investigated with the open Z-scan technique at 532 nm in the ns time regime. Most of the compounds exhibited a transmission drop with increasing input fl uence. This behavior is desirable for their applications in optical limiting. More complex responses: a drop in transmission followed by an increase in transmission or an increase in transmission followed by a transmission drop, with increasing input fl uence, were detected for certain compounds. All of the recorded responses were successfully fi tted with a four-level model with simultaneous two-photon absorption arising from the higher excited states (consecutive one- + one- + two-photon absorption). The TMS-ethynyl group was found to be a more e ffi cient meso substituent in optical limiting than the bromine atom. Indium, lead and zinc com- plexes with TMS-ethynyl substituents were the strongest positive nonlinear absorbers amongst com- pounds studied which makes them the most interesting candidates for optical limiting application.
Science Foundation Ireland (SFI)
SFI P.I. 09/IN.1/B265
Type of material:Journal Article
Series/Report no:Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology
Availability:Full text available
Keywords:positive nonlinear absorbers
Subject (TCD):Nanoscience & Materials