Primary charge-recombination in an artificial photosynthetic reaction center.
Photoinduced primary charge-separation and charge-recombination are characterized by a combination of time-resolved optical and EPR measurements of a fullerene-porphyrin-linked triad that undergoes fast, stepwise charge-separation processes. The electronic coupling for the energy-wasting charge recombination is evaluated from the singlet-triplet electronic energy gap in the short-lived, primary charge-separated state. The electronic coupling is found to be smaller by approximately 40% than that for the primary charge-separation. This inhibition of the electronic interaction for the charge-recombination to excited triplet state largely results from a symmetry-broken electronic structure modulated by configuration interaction between 3(b1u,b3g) and 3(au, b3g) electronic states of the free-base porphyrin.
Kobori
Yasuhiro
Y
Department of Chemistry, University of Chicago, Chicago, IL 60637, USA.
Yamauchi
Seigo
S
Akiyama
Kimio
K
Tero-Kubota
Shozo
S
Imahori
Hiroshi
H
Fukuzumi
Shunichi
S
Norris
James R
JR
D004583:Electrons; D037741:Fullerenes / Q000737:chemistry*; D008956:Models, Chemical; D036103:Nanotechnology; D010777:Photochemistry / Q000379:methods*; D045322:Photosynthetic Reaction Center Complex Proteins; D011166:Porphyrins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D037741:Fullerenes; D045322:Photosynthetic Reaction Center Complex Proteins; D011166:Porphyrins