Side Group of Poly(3-alkylthiophene)s Controlled Dispersion of Single-Walled Carbon Nanotubes for Transparent Conducting Film

Controlled dispersion of single-walled carbon nanotubes (SWCNTs) in common solvents is a challenging issue, especially for the rising need of low cost flexible transparent conducting films (TCFs). Utilizing conductive polymer as surfactant to facilitate SWCNTs solubility is the most successful pragmatic approach to such problem. Here, we show that dispersion of SWCNT with polymer significantly relies on the length of polymer side groups, which not only influences the diameter distribution of SWCNTs in solution, also eventually affects their effective TCF performance. Surfactants with longer side groups covering larger nanotube surface area could induce adequate steric effect to stabilize the wrapped SWCNTs against the nonspecific aggregation, as discerned by the optical and microscopic measurements, also evidenced from the resultant higher electrokinetic potential. This approach demonstrates a facile route to fabricate large-area SWCNTs-TCFs exhibiting high transmittance and high conductivity, with considerable uniformity over 10 cm × 10 cm

Understanding the Interplay between Molecule Orientation and Graphene Using Polarized Raman Spectroscopy

We present a systematic study in investigating the orientation characteristics of pentacene molecules grown on graphene substrates using polarized Raman spectroscopy. The substrate-induced orientation alignment of pentacene can be well distinguished through the polarized Raman spectra. Interestingly, we found that the nature of polycrystalline graphene not only provides efficient route to control molecular orientation, but also acts as an excellent template allowing conjugated molecules to stack accordingly. The relative orientation of the well-aligned pentacene molecules and the nearby graphene domains exhibits several preferred angles due to atomic interactions. This unique feature is further examined and verified by single domain graphene. Furthermore, polarized Raman spectroscopy contains abundant information allowing us to analyze the ordering level of pentacene films with various thicknesses, which provides insightful perspectives of manipulating molecular orientations with graphene and spatial organization between conjugated systems, in a more quantitative manner