We report the first optical waveguide based on perylene diimide (PDI) crystalline microwires. The birefringence, polarized photoluminescence emission, long distance light waveguide as well as electrical‐optical modulation were studied. PDI is a good polymeric electro‐optic material because of its low relative permittivity, low operating voltage, high thermal and photo‐stability, and easy integration on flexible substrates.

The dual role of graphene (or reduced graphene oxide) as atomic template and structural scaffold in the nucleation and assembly of organic nanostructures is demonstrated. The π-π stacking interactions between graphene and aromatic organic molecules affords synergistic binding interactions, with the host and guest assuming the interchangeable roles of atomic template and structural scaffold. Beginning with the seeding of organic wires on graphene template, the outgrown organic wires in turn act as one-dimensional scaffolds where graphene sheets coat around to form a unique graphene-organic hybrid structure. Using this π-assembly approach, we have synthesized one-dimensional hybrid structures consisting of graphene-N,N'-dioctyl-3,4,9,10-perylenedicarboximide (PDI) organic wires. This hybrid structure shows enhanced performance over its individual components in donor-acceptor type (PDI-Graphene/polythiophene) solar cells.

The transformation of two-dimensional graphene oxide (GO) nanosheets into carbon nanotubes was achieved by sonicating GO in 70% nitric acid. Through the use of mass spectrometry to track the evolution of molecular fragments during the acid ultrasonication, it was observed that GO can be readily decomposed into polyaromatic hydrocarbons (PAHs). The cavitation-induced condensation of these PAHs results in their molecular reconstruction to form folded carbon nanostructures. UV-emitting, water-soluble carbon nanoparticles as well as carbon nanotubes that exhibit magnetic properties were fabricated under catalyst-free conditions.

Motivated by its high surface area and electrical conductivity, reduced graphene oxide (rGO) flakes have been intensively studied as potential anode materials for lithium ion battery (LIB). The high capacity in rGO (600–1000 mA h g–1) compared to graphite (372 mA h g–1) suggest that a different lithiation mechanism may be operational in the former. The high capacity of rGO should be attributed to its high surface area and associated defective sites, however, these may act as trapping sites and undergo side reactions with the solvent and lithium ions to form the solid electrolyte interphase (SEI) upon lithiation, resulting in irreversible capacity loss (ICL) during the initial cycles. Elucidating the temporal evolution of SEI layer on rGO and quantifying the amount of trapped lithium will be useful in developing strategies to mitigate the ICL process. Herein, the Li intercalation mechanism in rGO and graphite was investigated using in situ Raman spectroscopy and in situ time-resolved nuclear magnetic resonance (NMR) to provide insights into the origins of the high capacity and ICL loss in rGO. Finally, the dynamic and static SEI passive layer formed on rGO flakes was monitored, and a method was developed to quantify the amount of Li+ trapped in the SEI layer.