Search

A nanocomposite of multiwalled carbon nanotubes (CNTs) and poly(3-hexylthiophene) (P3HT) was prepared by grafting P3HT uniformly on the surface of CNTs (P3HT/P3HT- g-CNT) via a 'grafting from' method with the coating thicknesses controlled. It was found that as the coating thickness decreased, the crystallinity of the P3HT decreased, along with significant red-shifting of Raman that signified alterations of chain conformation. Furthermore, although the photoluminescence (PL) peak remained unchanged when grafted on CNTs, modifications of P3HT energy gap was observed, indicating variations of vibronic levels arising from the grafting. Moreover, broadening of the PL emission took place that suggested decreasing of lifetimes of the photo-generated species when grafted on CNTs. Bilayer photovoltaic devices with the (6,6)-phenyl C61-butyric acid methyl ester as the electron acceptor have shown that the nanocomposite P3HT/P3HT- g-CNT performed much more efficiently as the electron donor, in both photocurrent density and power conversion efficiency, compared with the neat P3HT. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 [ABSTRACT FROM AUTHOR]

The anatase crystallization behaviors in ionothermal synthesis (sol–gel method containing ionic liquid) of nanostructured TiO2 were studied in this paper. It was found that the specific physical chemical characteristics of the water/ionic liquid mixture caused the formation path and crystallinity of anatase TiO2 to depend on the H2O/titanium dioxide precursor (titanium tetraisopropoxide, TIP) molar ratio. Hydroxylated titanium compound was a key intermediate for forming anatase TiO2. It could be directly formed from hydrolysis of titanium dioxide precursor or ionic liquid-induced water dissolution of the condensation product. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) data indicated that a higher hydroxyl group ratio content of hydroxylated titanium compound was obtained at medium H2O/TIP molar ratio and from the system containing hydrophilic ionic liquid, such as 1-butyl-3-methylimidazolium tetrafluoroborate ([BuMIm]+[BF4]−). The self organization ability of ionic liquid drove anatase crystallization through dehydration of the Ti–OH group of hydroxylated titanium compound in the thermal annealing process. As for the particle size of TiO2, TEM results indicated smaller particle size of TiO2 was obtained at medium H2O/TIP molar ratio case. [ABSTRACT FROM AUTHOR]