Low-temperature one-step synthesis of covalently chelated ZnO/dopamine hybrid nanoparticles and their optical properties

Dopamine covalently chelated ZnO nanoparticles were synthesized by a nonaqueous one-step chemical process at a temperature as low as 60 degrees C. The formation of ZnO/dopamine hybrid structure was proved by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) techniques. Detailed absorption, luminescence, and time-resolved decay studies were performed for these ZnO/dopamine hybrid nanoparticles. We observed an enhanced green emission, which could be assigned to a new band-gap emission based on the fast of nanosecond lifetime of the green emission. Our results demonstrated that the change of optical properties of ZnO nanoparticles after covalently chelated by dopamine ligands is closely associated with the formation of new band structure.