Electron Injection of Phosphorus Doped g‐C3N4 Quantum Dots: Controllable Photoluminescence Emission Wavelength in the Whole Visible Light Range with High Quantum Yield

The large band gap (2.7 eV) of graphite‐like carbon nitride (g‐C3N4) enables the g‐C3N4 quantum dots (g‐C3N4 QDs) to show near ultraviolet‐blue photoluminescence. This study demonstrates the effective band gap control of g‐C3N4 QDs by phosphorus doping for the first time. With the electronic injection process of lattice doped P, the band gap decreased observably. The emission wavelength of phosphorus doped g‐C3N4 QDs (P‐g‐C3N4 QDs) can be tuned in whole visible light range (385–762 nm) by changing the doping concentration. Due to the direct band gap of these P‐g‐C3N4 QDs, the quantum yield is higher than 0.90. The authors also show the application value of these P‐g‐C3N4 QDs in both in vitro and in vivo fluorescent bio‐imaging.