Precursor-Dependent Blue-Green Photoluminescence Emission of ZnO Nanoparticles

We report on properties of ZnO nanoparticles synthesized via non-aqueous sol–gel routes. The role of the hydrates in the zinc precursor (Zn(acac) 2, xH 2 O) on the structure and surface termination during the synthesis is studied for the first time. The structural and chemical properties of the ZnO nanoparticles were studied by standard structural and optical characterization methods. A broad luminescence was observed from the nanoparticles stretching throughout the visible region of the spectrum and comprising characteristic blue and green emission bands commonly associated with intrinsic defects in ZnO. A tentative model is proposed to explain differences in the luminescence of nanoparticles synthesized using different routes by taking into account the role of oxygen vacancies and other native defects: most likely being zinc vacancies and interstitials, located near the surface of the nanoparticles.