Real-time observation of ultrafast electron injection at graphene-Zn porphyrin interfaces

Real-time observation of ultrafast electron injection at graphene-Zn porphyrin interfaces

Real-time observation of ultrafast electron injection at graphene-Zn porphyrin interfaces
Omar F. Mohammed, Dilshad Masih, Shawkat Aly, Anwar Usman and Erkki Alarousu 
Phys. Chem. Chem. Phys., 17, 9015-9019, (2015)
Omar F. Mohammed, Dilshad Masih, Shawkat Aly, Anwar Usman and Erkki Alarousu
Ultrafast electron injection, Graphene-Zn porphyrin interfaces
2015
We report on the ultrafast interfacial electron transfer (ET) between zinc (II) porphyrin (ZnTMPyP) and negatively charged graphene carboxylate (GC) using state-of-the art femtosecond laser spectroscopy with broadband capabilities. The steady-state interaction between GC and ZnTMPyP results in a red-shifted absorption spectrum, providing clear indication for the binding affinity between ZnTMPyP and GC via electrostatic an pi-pi stacking interactions. Ultrafast transient absorption (TA) spectra in the absence and presence of three different GC concentrations reveal (i) the ultrafast formation of singlet excited ZnTMPyP*, which partially relaxes into a long-lived triplet state, and (ii) ET from the singlet excited ZnTMPyP* to GC, forming ZnTMPyP●+ and GC●-, as indicated by a spectral feature at 650-750 nm, which is attributed to a ZnTMPyP radical cation resulting from the ET process.



DOI: 10.1039/C4CP06050D