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Improving Photocurrent Generation: Supramolecularly and Covalently Functionalized Single‐Wall Carbon Nanotubes–Polymer/Porphyrin Donor–Acceptor Nanohybrids
Author(s) -
Rahman G. M. Aminur,
Troeger Anna,
Sgobba Vito,
Guldi Dirk M.,
Jux Norbert,
Balbino Domenico,
Tchoul Maxim N.,
Ford Warren T.,
MateoAlonso Aurelio,
Prato Maurizio
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801018
Subject(s) - carbon nanotube , covalent bond , photocurrent , acceptor , polymer , non covalent interactions , supramolecular chemistry , photochemistry , chemistry , van der waals force , porphyrin , materials science , polymer chemistry , nanotechnology , organic chemistry , hydrogen bond , molecule , physics , optoelectronics , condensed matter physics
Electrostatic interactions : A versatile donor–acceptor system has been constructed by exploiting the electrostatic interactions between covalently and noncovalently polymer‐functionalized SWNTs (i.e., SWNT–PVBTA n + and SWNT/PVBTA n + ) and porphyrins (i.e., H 2 P 8− or ZnP 8− ). The nanohybrids thus formed afford long‐lived radical–ion pairs and valuable photocurrent conversions (see figure).Novel nanohybrids based on covalently and noncovalently functionalized single‐wall carbon nanotubes (SWNTs) have been prepared and assembled for the construction of photoactive electrodes. Polymer‐grafted SWNTs were synthesized by free‐radical polymerization of (vinylbenzyl)trimethylammonium chloride. Poly[(vinylbenzyl)trimethylammonium chloride] (PVBTA n + ) was also noncovalently wrapped around SWNTs to form stable, positively charged SWNT/PVBTA n + suspensions in water. Versatile donor–acceptor nanohybrids were prepared by using the electrostatic/van der Waals interactions between covalent SWNT–PVBTA n + and/or noncovalent SWNT/PVBTA n + and porphyrins (H 2 P 8− and/or ZnP 8− ). Several spectroscopic, microscopic, transient, and photoelectrochemical measurements were taken to characterize the resulting supramolecular complexes. Photoexcitation of the nanohybrids afforded long‐lived radical ion pairs with lifetimes as long as 2.2 μs. In the final part, photoactive electrodes were constructed by using a layer‐by‐layer technique on an indium tin oxide covered glass support. Photocurrent measurements gave remarkable internal photon‐to‐current efficiencies of 3.81 and 9.90 % for the covalent ZnP 8− /SWNT–PVBTA n + and noncovalent ZnP 8− /SWNT/PVBTA n + complex, respectively, when a potential of 0.5 V was applied.