Fabrication of g-C3N4 films with enhanced mechanical and charge transfer properties by electrophoretic deposition and subsequent citric acid modification

A low-cost 2D metal-free material based on a graphitic carbon nitride (g-C3N4) film functionalized with a citric acid molecule has been successfully fabricated by Electrophoretic Deposition (EPD) and thermal techniques, aiming to evaluate its suitability for optoelectronic devices. The thickness-controlled g-C3N4 film having a good mechanical property was successfully performed. The chemical stability and photostability of the citric-modified g-C3N4 films deposited on indium tin oxide (ITO) glass were investigated. New chemical links were clarified such that it could possibly become a bridge for enhancing charge transport. The modified samples exhibited a significant increase in their photocurrent response, reaching 25 μA/cm2 at a thickness of about 20 μm. Electrochemical impedance spectra (EIS) verified the enhanced conductivity, efficient charge transfer, and reduced electron-hole recombination rate. This research revealed a facile synthetic route and environmentally benign materials, thereby suggesting promising prospects for their application in the optoelectronic field.