Picosecond dynamics of intramolecular charge-transfer processes of β-substituted porphyrins adsorbed on the porous glass

Intramolecular charge separation and charge recombination dynamics of 2,8,12,18-tetrakis(9-anthryl) substituted porphyrin (PA) adsorbed on porous glass were investigated. It was found that the porphyrin moiety adsorbed on the porous glass was protonated to form a dication which accepts an electron from the anthryl moiety. The application of picosecond transient absorption spectroscopy and time-resolved fluorescence measurements revealed that the charge transfer in the excited state of PA took place within 7 ps after the excitation even in the adsorbed system. The rapid intramolecular charge separation process in the adsorbed state without polar solvents was discussed by comparing the present result with those in solutions.