Charge transfer enhances two-photon absorption in transition metal porphyrins.
Two-photon absorption processes were investigated in electropolymerized Fe(III), Mn(III), and Co(II) 5,10,15,20-tetrakis-(4-hydroxytetraphenyl)porphyrin films. Degenerate four wave mixing (DFWM) spectroscopy with 100 fs pulses in the near-IR spectral region was used. Metalloporphyrins with strong charge transfer (CT) transitions in the linear absorption spectra also show enhanced two-photon absorption. (Metalloporphyrin two-photon absorption cross section, delta, increases >10 times over that for the metal free porphyrin.) This effect was attributed to a two-photon induced charge transfer between the metal ion's d orbitals and the pi-system of the porphyrin. Correlation of one- and two-photon absorption properties of transition metal porphyrins suggests a new and simple approach to improve organic materials for photonic applications.
Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284-2006, USA.
Jonathan L
JL
Humphrey
Darius
D
Kuciauskas
D003035:Cobalt / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D008345:Manganese / Q000737:chemistry; D008665:Metalloporphyrins / Q000737:chemistry*; D017785:Photons; D011166:Porphyrins / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods
D005290:Ferric Compounds; D008665:Metalloporphyrins; D011166:Porphyrins; C409084:tetraphenylporphyrin; D003035:Cobalt; D008345:Manganese