TY - JOUR
T1 - Diameter-sorted SWCNT-porphyrin and SWCNT-phthalocyanine conjugates for light-energy harvesting
AU - Sandanayaka, Atula S.D.
AU - Subbaiyan, Navaneetha K.
AU - Das, Sushanta K.
AU - Chitta, Raghu
AU - Maligaspe, Eranda
AU - Hasobe, Taku
AU - Ito, Osamu
AU - D'Souza, Francis
PY - 2011/8/22
Y1 - 2011/8/22
N2 - A non-covalent double-decker binding strategy is employed to construct functional supramolecular single-wall carbon nanotubes (SWCNT)-tetrapyrrole hybrids capable of undergoing photoinduced electron transfer and performing direct conversion of light into electricity. To accomplish this, two semiconducting SWCNTs of different diameters (6,5 and 7,6) were modified via π-π stacking of pyrene functionalized with an alkyl ammonium cation (PyrNH3+). Such modified nanotubes were subsequently assembled via dipole-cation binding of zinc porphyrin with one (1) or four benzo-18-crown-6 cavities (2) or phthalocyanine with four benzo-18-crown-6 cavities at the ring periphery (3), employed as visible-light photosensitizers. Upon charactering the conjugates using TEM and optical techniques, electron transfer via photoexcited zinc porphyrin and phthalocyanine was investigated using time-resolved emission and transient absorption techniques. Higher charge-separation efficiency is established for SWCNT(7,6) with a narrow band gap than the thin SWCNT(6,5) with a wide band gap. Photoelectrochemical studies using FTO/SnO2 electrodes modified with these donor-acceptor conjugates unanimously demonstrated the ability of these conjugates to convert light energy into electricity. The photocurrent generation followed the trend observed for charge separation, that is, incident-photon-to-current efficiency (IPCE) of a maximum of 12% is achieved for photocells with FTO/SnO 2/SWCNT(7,6)/PyrNH3+:1.
AB - A non-covalent double-decker binding strategy is employed to construct functional supramolecular single-wall carbon nanotubes (SWCNT)-tetrapyrrole hybrids capable of undergoing photoinduced electron transfer and performing direct conversion of light into electricity. To accomplish this, two semiconducting SWCNTs of different diameters (6,5 and 7,6) were modified via π-π stacking of pyrene functionalized with an alkyl ammonium cation (PyrNH3+). Such modified nanotubes were subsequently assembled via dipole-cation binding of zinc porphyrin with one (1) or four benzo-18-crown-6 cavities (2) or phthalocyanine with four benzo-18-crown-6 cavities at the ring periphery (3), employed as visible-light photosensitizers. Upon charactering the conjugates using TEM and optical techniques, electron transfer via photoexcited zinc porphyrin and phthalocyanine was investigated using time-resolved emission and transient absorption techniques. Higher charge-separation efficiency is established for SWCNT(7,6) with a narrow band gap than the thin SWCNT(6,5) with a wide band gap. Photoelectrochemical studies using FTO/SnO2 electrodes modified with these donor-acceptor conjugates unanimously demonstrated the ability of these conjugates to convert light energy into electricity. The photocurrent generation followed the trend observed for charge separation, that is, incident-photon-to-current efficiency (IPCE) of a maximum of 12% is achieved for photocells with FTO/SnO 2/SWCNT(7,6)/PyrNH3+:1.
KW - crown ethers
KW - electron transfer
KW - nanotubes
KW - photoelectrochemistry
KW - self-assembly
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U2 - 10.1002/cphc.201100377
DO - 10.1002/cphc.201100377
M3 - Article
C2 - 21751336
AN - SCOPUS:80051737593
SN - 1439-4235
VL - 12
SP - 2266
EP - 2273
JO - ChemPhysChem
JF - ChemPhysChem
IS - 12
ER -