Buckminsterfullerenes have been conjugated to CdSe nanocrystals by exchanging TOPO ligands on the CdSe nanocrystals with C₆₀-bound dithiocarbamate ligands. To improve solubility of the C₆₀-capped CdSe nanocrystals, a small molecular weight dithiocarbamate ligand was used as co-ligand in the ligand exchange reaction. The as synthesized (C₆₀)₈-CdSe conjugates were purified by dialysis against ethanol and characterized by ¹H NMR, UV-vis and TEM. Photoelectrochemistry of a film cast from the (C₆₀)₈-CdSe conjugate revealed a significantly enhanced photocurrent compared with the film of CdSe-TOPO nanocrystals as well as that of C₆₀ alone, suggesting that our conjugation strategy is viable for efficient photo-induced charge separation, transport and collection. ₆₀...[ Read more ]

Buckminsterfullerenes have been conjugated to CdSe nanocrystals by exchanging TOPO ligands on the CdSe nanocrystals with C₆₀-bound dithiocarbamate ligands. To improve solubility of the C₆₀-capped CdSe nanocrystals, a small molecular weight dithiocarbamate ligand was used as co-ligand in the ligand exchange reaction. The as synthesized (C₆₀)₈-CdSe conjugates were purified by dialysis against ethanol and characterized by ¹H NMR, UV-vis and TEM. Photoelectrochemistry of a film cast from the (C₆₀)₈-CdSe conjugate revealed a significantly enhanced photocurrent compared with the film of CdSe-TOPO nanocrystals as well as that of C₆₀ alone, suggesting that our conjugation strategy is viable for efficient photo-induced charge separation, transport and collection.

C₆₀ has been conjugated to PbSe by using the similar strategy to that of the C₆₀-CdSe nanoconjugate in Chapter 1. The as synthesized C₆₀-PbSe conjugates were characterized by H NMR, UV-Vis and TEM. The H NMR study shows that the dithiocarbamate ligands has stronger interaction with PbSe nanocrystals than that with CdSe nanocrystals. Photoelectrochemistry of a film cast from the C₆₀-PbSe nanoconjugate revealed a cathodic photocurrent, although the individual C₆₀ and PbSe nanocrystals generated anodic photocurrent respectively. The reversed polarity of the photocurrent suggesting the C₆₀ can serve as p-dopants to the PbSe nanocrystals through the surface transfer doping process.

A Cu(I)-assisted C₆₀-polymerization method has been developed for the seamless coating on nanosized objects of Cu₂O, forming novel Cu₂O-C₆₀ core-shell nanostructures. It is based on a reaction of C₆₀ and ethyl isocyanoacetate to form polymerized fulleropyrolines, catalyzed by and thus coated on the Cu₂O nanomaterials. Cu₂O nanoribbons and nanocubes were used in this work to demonstrate the nano-coating method. The Cu₂O-C₆₀ core-shell nanostructures were characterized comprehensively, revealing a uniform, covalently-polymerized C₆₀ shell that closely sheaths the Cu₂O nanostructures. Details of the Cu(I)-assisted C₆₀-polymerization process are proposed, which combines the solution chemistry and surface chemistry of C₆₀. The Cu₂O cores in the composite nanocubes could be removed, yielding monodispersed C₆₀ nanoboxes. Preliminary measurements demonstrated enhanced photocurrent of the Cu₂O-C₆₀ nanoribbons arrayed on Cu foil compared to that of the Cu₂O nanoribbons.

Two strategies have been explored for organic functionalizations of ZnO nanotetrapods via anchor groups of carboxylate and phosphonate. With these methods, oleyl chains were assembled on surfaces of the ZnO nanotetrapods, significantly enhancing their solubility in nonpolar solvents, such as chloroform and toluene. The surface functionalization strategies have been extended to electroactive and photoactive molecules such as protoporphyrin and C₆₀ on the ZnO nanotetrapods. The surface modified ZnO nanotetrapods were characterized comprehensively, revealing a uniform, covalently linked monolayer assembled on the surface. This work opens a broad perspective for the application of the organically functionalized nanotetrapods in optoelectronics and biomedicine.

Two-photon luminescence (TPL) spectra were measured to study the effect of protoporphyrin and C₆₀ to TPL properties of ZnO nanotetrapods. The results show that after modifying with protoporphyrin, the exciton emission of the ZnO nanotetrapods was red-shift for about 30 nm, which may be due to the surface charge transfer doping of protoporphyrin to ZnO nanotetrapods. After modified with C₆₀, the TPL spectrum of ZnO nanotetrapods was obviously enhanced to the exposure of laser with the intensity of 140 mW. The stable C₆₀-ZnO nanocomposites may have applications in the nonlinear optical devices.