Donor‐Acceptor Substituted Carbon Nitride Enables Efficient and Colorful Phosphors

Abstract Graphitic carbon nitride (g‐CN) is a polymeric semiconductor with low‐cost synthesis, adjustable structure, and excellent stability, which attracts great attention and is widely used as a photocatalyst. On the contrary, it isn't considered as a promising fluorescent material due to the inefficient radiative recombination of electron‐hole pairs. Here, efficient and multicolor‐emitting g‐CN phosphors are presented by integrating donor‐acceptor substituents in order to replace the expensive rare earth‐based phosphors. By incorporating phenyl as a donor and benzonitrile as an acceptor, the aromatic groups enhance the structural rigidity of g‐CN and improve the photoluminescence (PL) efficiency; meanwhile, the donor‐acceptor extends the π ‐conjugated system of g‐CN, promotes the electron delocalization and results in tunable PL spectra. As a result, the donor‐acceptor substituted g‐CN materials exhibit blue to yellow light emission and reach a record photoluminescence quantum yield (PLQY) of 57%. A white light‐emitting diode is fabricated by combining the modified g‐CN phosphors and commercial 450 nm blue chips, which produce a bright white light emission with chromaticity coordinates of (0.34, 0.32). The findings provide a rational design for a high‐performance g‐CN emitter and highlight the potential applications of g‐CN in optoelectronic devices and indoor lighting.