Controllable synthesis of Eu³⁺-doped Y₂O₃ nanocrystal/g-C₃N₄ composites with tunable fluorescence

The application of graphitic carbon nitride (g-C₃N₄) has been restricted in some optoelectronics fields due to its narrow tunable emission region. In order to engineer the optical properties, herein we combine Eu³⁺:Y₂O₃ nanocrystals with g-C₃N₄to control its electronic structure. Surprisingly, with the increasing concentration of Eu³⁺:Y₂O₃ nanocrystals, the photoluminescence of Eu³⁺:Y₂O₃/g-C₃N₄ (EYCN) showed a continuous red shift in comparison with pure g-C₃N₄ from blue to green. In EYCN composites, the Eu³⁺:Y₂O₃ nanocrystals as electron donors, can improve the degree of electron delocalization and narrow the bandgap. Importantly, the EYCN composites not only maintain the intrinsic blue-green emission of g-C₃N₄, but also introduce the red light of Eu³⁺ ions. Based on the EYCN composites, white light-emitting diode (WLED) were fabricated with a Commission International de L’Eclairage value of (0.3631, 0.3560). This work proposes a new kind of luminescent g-C₃N₄-based composites, which is expected to broaden its applications in optoelectronics field.