jp302178q_si_001.pdf (458.96 kB)
Carbon Nanohorn–Porphyrin Dimer Hybrid Material for Enhancing Light-Energy Conversion
journal contribution
posted on 2012-05-03, 00:00 authored by Georgia Pagona, Galateia
E. Zervaki, Atula S. D. Sandanayaka, Osamu Ito, Georgios Charalambidis, Taku Hasobe, Athanassios G. Coutsolelos, Nikos TagmatarchisThe covalent grafting through a rigid ester bond of a
dimeric porphyrin
[(H2P)2] and carbon nanohorns (CNHs) was accomplished.
The newly formed CNH–(H2P)2 hybrid was
found to be soluble or dispersible in several organic solvents. Application
of diverse spectroscopic techniques verified the successful formation
of the CNH–(H2P)2 hybrid material. In
addition, thermogravimetric analysis revealed the amount of (H2P)2 loading onto CNHs, and TEM studies showed the
characteristic secondary spherical superstructure morphology of the
hybrid material. Efficient fluorescence quenching of (H2P)2 in the CNH–(H2P)2 hybrid
suggests that photoinduced events occur from the photoexcited (H2P)2 to CNHs. Nanosecond transient absorption spectroscopy
revealed the formation of transient species such as (H2P)2•+ and CNH•– by photoinduced charge separation in CNH–(H2P)2. Additional proof for the photoinduced charge-separated state
CNH•––(H2P)2•+ was obtained, from which the electron mediates
to added hexyl viologen dication (HV2+). Finally, the CNH–(H2P)2 was adsorbed on nanostructured SnO2 electrode, to construct a photoactive electrode, which reveals photocurrent
and photovoltage responses with an incident photon-to-current conversion
efficiency value as large as 9.6%, without the application of any
bias voltage.
