A facile route to synthesize hydrophilically or hydrophobically grafted graphitic carbon nitride (g-CN) is reported. For this purpose, functionalized olefinic molecules with a low polymerization tendency are utilized for grafting onto the surface to preserve the features of g-CN while improving its dispersibility. One-pot, visible light-induced grafting yields highly dispersible g-CNs either in aqueous or organic media. Moreover, functional groups such as amines can be introduced, which yields pH-dependent dispersibility in aqueous media. Compared with unfunctionalized g-CN, low sonication times are sufficient to redisperse g-CN. In addition, because of increased dispersion stability, higher amounts of functionalized g-CN can be dispersed (up to 10% in aqueous dispersion and 2% in organic dispersion) when compared to unfunctionalized g-CN.

The utilization of graphitic carbon nitride (g-CN) as photoinitiator for hydrogel formation is reported. On top of the photochemical activity, g-CN entails the role of a reinforcing agent. Hydrogels formed via g-CN (0.6 wt % g-CN and 11 wt % solid content in total) possess significantly increased mechanical strength, around 32 times stronger storage moduli (from 250 Pa for the reference sample up to 8300 Pa for g-CN derived hydrogels) than the ones initiated with common radical initiators. In addition, the g-CN derived hydrogels show mechanical properties that are pH dependent. Therefore, g-CN acts as a photoinitiator for hydrogel formation and as reinforcer at the same time.

The present review highlights the combination of graphitic carbon nitride and polymers for materials with outstanding properties.

Covalent modification of phenyl-modified carbon nitride with vinylthiazole groups via visible light induced grafting is reported. Modified structures express negative charge migration to the thiazole edges while the carbon nitride sheet remains positively charged in organic solutions. Such a phenomenon provides electrostatic stabilization of modified carbon nitride particles in organic media leading to highly organodispersible and colloidally stable carbon nitrides. The resulting structures can be homogeneously dispersed in organic solvents and can be cast to transparent films. The usefulness of such a processable colloidal carbon nitride building block is exemplified here by its high luminescence and inkjet printing of films.

Effective, solution-processable designs of interfacial electron-transporting layers (ETLs) or hole-blocking layers are promising tools in modern electronic devices, e.g., to improve the performance, cost, and stability of perovskite-based solar cells. Herein, we introduce a facile synthetic route of thiazole-modified carbon nitride with 1.5 nm thick nanosheets which can be processed to a homogeneous, metal-free ETL for inverted perovskite solar cells. We show that thiazole-modified carbon nitride enables electronic interface enhancement via suppression of charge recombination, achieving 1.09 V in V oc and a rise to 20.17 mA/cm2 in J sc. Hence, this report presents the successful implementation of a carbon-nitride-based structure to boost charge extraction from the perovskite absorber toward the electron transport layer in p-i-n devices.