In this study, we demonstrate that plasma treatment can be a facile and environmentally friendly approach to perform surface modification of graphitic carbon nitride (g-CN), leading to a remarkable modulation on its photocatalytic activity. The bulk properties of g-CN, including the particle size, structure, composition, and electronic band structures, have no changes after being treated by oxygen or nitrogen plasma; however, its surface composition and specific surface area exhibit remarkable differences corresponding to an oxygen functionalization induced by the plasma post-treatment. The introduced oxygen functional groups play a key role in reducing the recombination rate of the photoexcited charge carries. As a consequence, the oxygen-plasma-treated sample shows a much superior photocatalytic activity, which is about 4.2 times higher than that of the pristine g-CN for the degradation of rhodamine B (RhB) under visible light irradiation, while the activity of nitrogen-plasma-treated sample exhibits a slight decrease. Furthermore, both of the plasma-treated samples are found to possess impressive photocatalytic stabilities. Our results suggest that plasma treatment could be a conventional strategy to perform surface modification of g-CN in forms of both powders and thin films, which holds broad interest not only for developing g-CN-based high-performance photocatalysts but also for constructing photoelectrochemical cells and photoelectronic devices with improved energy conversion efficiencies.

We investigate the molecular orientation transition and resulting morphology of copper phthalocyanine (CuPc) thin films induced by solvent-vapour annealing (SVA) in detail. Seven solvents are utilized to tune the morphology of CuPc thin films. The morphology, crystalline structure and optical properties of the CuPc active layer were investigated through field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) absorption spectrum, respectively. The result demonstrates that morphology and structure are depended on the type of solvents. The high crystallinity of the CuPc films with a larger grain size and less grain boundaries can be observed. As a result, the resistance of the conducting channel is decreased, leading to an improved performance of the organic field-effect transistor (OFET).

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