A series of ZnP-pCp-oPPV-C60 conjugates covalently connected through [2,2']-paracyclophane-oligophenylenevinylene (pCp-oPPV) bridges containing one, two, and three [2,2']-paracyclophanes (pCps) has been prepared in multistep synthetic procedures involving Horner-Wadsworth-Emmons olefination reactions and/or Heck type Pd-catalyzed reactions. Molecular modeling suggests that charge transfer is effectively mediated by the pCp-oPPVs through a predominant hole-transfer mechanism. Photophysical investigation supports molecular modeling and reveals two major trends. On one hand, C60 excitation of 1, 2, and 3 leads exclusively to charge transfer between pCp and C60 to afford a ZnP-(pCp-oPPV)(•+)-C60(•-) radical ion pair state without giving rise to a subsequent charge shift to yield the ZnP(•+)-pCp-oPPV-C60(•-) radical ion pair state. On the other hand, ZnP excitation of 1, 2, and 3 results in a rather slow charge transfer between ZnP and C60, after which the ZnP(•+)-pCp-oPPV-C60(•-) radical ion pair state evolves. In temperature-dependent ZnP fluorescence experiments, which were performed in the temperature range from 273 to 338 K, two domains are discernible: low and high temperature behaviors. In the low temperature range (i.e., below 30 °C) the rate constants do not change, suggesting that a superexchange mechanism is the modus operandi. In the high temperature range (i.e., >30 °C) the rate constants increase. Moreover, we find rather strong distance dependence for 1 and 2 and weak distance dependence for 2 and 3. A damping factor of 0.145 Å(-1) is derived for the former pair and 0.012 Å(-1) for the latter.

Approaches for the selective self-assembly of functionalized carbon allotropes from solution are developed and validated for 0D-fullerenes, 1D-carbon nanotubes and 2D-graphene. By choosing the right molecular interaction of self-assembled monolayers (serving the surface) with the functionalization features of carbon materials, which provide the solubility but also serve the driving force for assembly, we demonstrate a region-selective and self-terminating assembly of the materials. Active layers of the carbon allotropes can be selectively deposited in the channel region of thin-film transistor (TFT) devices by this approach. As an example for a 0D system, molecules of C60 functionalized octadecylphosphonic acids are used to realize self-assembled monolayer field-effect transistors (SAMFETs) based on a selective molecular exchange reaction of stearic acid in the channel region. For noncovalently functionalized single-walled carbon nanotubes (SWCNTs) and graphene oxide (GO) flakes, the electrostatic Coulomb interactions between the functional groups of the carbon allotropes and the charged head groups of a SAM dielectric layer are utilized to implement the selective deposition.

We use vibrational sum-frequency generation (VSFG) spectroscopy to study the structure of hen egg-white lysozyme (HEWL) aggregates adsorbed to DOPG/D 2 O and air/D 2 O interfaces. We find that aggregates with a parallel and antiparallel β-sheet structure together with smaller unordered aggregates and a denaturated protein are adsorbed to both interfaces. We demonstrate that to retrieve this information, fitting of the VSFG spectra is essential. The number of bands contributing to the VSFG spectrum might be misinterpreted, due to interference between peaks with opposite orientation and a nonresonant background. Our study identified hydrophobicity as the main driving force for adsorption to the air/D 2 O interface. Adsorption to the DOPG/D 2 O interface is also influenced by hydrophobic interaction; however, electrostatic interaction between the charged protein's groups and the lipid's headgroups has the most significant effect on the adsorption. We find that the intensity of the VSFG spectrum at the DOPG/D 2 O interface is strongly enhanced by varying the pH of the solution. We show that this change is not due to a change of lysozyme's and its aggregates' charge but due to dipole reorientation at the DOPG/D 2 O interface. This finding suggests that extra care must be taken when interpreting the VSFG spectrum of proteins adsorbed at the lipid/water interface.

We use surface-specific heterodyne-detected vibrational sum-frequency generation spectroscopy (HD-VSFG) and surface tension measurements to investigate the molecular structure of the surface of aqueous solutions of poly(vinyl alcohol) (PVA) polymers with average molecular weights of 10000 and 125000 g/mol. We find that the interfacial water molecules have a preferred orientation with their hydrogen-bonded O−H groups pointing away from the bulk, for both PVA 10000 and PVA 125000 . This observation is explained from the ongoing hydrolysis of the acetyl impurities on the PVA polymer chains. This hydrolysis yields negatively charged acetate ions that have a relatively high surface propensity. For both PVA 10000 and PVA 125000 the strong positive signal vanishes when the pH is decreased, due to the neutralization of the acetate ions. For solutions with a high concentration of PVA 10000 the interfacial water signal becomes very small, indicating that the surface gets completely covered with a disordered PVA polymer film. In contrast, for high concentrations of PVA 125000 , the strong positive water signal persists at high pH, which shows that the water surface does not get completely covered. The HD-VSFG data combined with surface tension data indicate that concentrated PVA 125000 solutions form a structured surface layer with pores containing a high density of interfacial water.

A method for the region-selective deposition of nanoparticles (NPs) by the Huisgen 1,3-dipolar cycloaddition is presented. The approach enables defined stacking of various oxide NPs in any order with control over layer thickness. Thereby the reaction is performed between a substrate, functionalized with a self-assembled monolayer of an azide-bearing phosphonic acid (PA) and aluminum oxide (AlO(x)) NPs functionalized with an alkyne bearing PA. The layer of alkyne functionalized AlO(x) NPs is then used as substrate for the deposition of azide-functionalized indium tin oxide (ITO) NPs to provide a binary stack. This progression is then conducted with alkyne-functionalized CeO2 NPs, yielding a ternary stack of NPs with three different NP cores. The stacks are characterized by AFM and SEM, defining the region-selectivity of the deposition technique. Finally, these assemblies have been tested in devices as a dielectric to form a capacitor resulting in a dramatic increase in the measured capacitance.