Luminescence of ZnO nanocrystals capped with an organic dye

ZnO nanocrystals capped with an organic dye Rhodamine 6G (Rh6G) were investigated by photoluminescence (PL) and cathodoluminescence (CL) techniques. PL and CL spectra showed a remarkable decrease in visible emission intensity after ZnO nanocrystals were capped with Rh6G, indicating that dangling bonds and defect states existing at the surface of ZnO nanocrystals were significantly passivated. Rh6G on the ZnO surface exhibited a monomer-like emission, and the intensity and the position of the emission were dependent on the dye concentration.