Abstract
The study of micro-/nanohybrid materials is an emerging area of nanoscience and nanotechnology. Here we report an investigation on the preparation and physicochemical characterization of pure ZnO and hybrid ZnO-porphyrin fine particles systems. ZnO particles were prepared from zinc acetate dihydrate and sodium hydroxide solution in methanol at 60 degrees C which were then surface functionalized with meso-tetraphenylporphine disulphonic acid dihydrochloride (TPPS2). The particles were characterized by using UV-visible spectrophotometry (UV), fluorescence emission (PL), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Band gap energy of ZnO fine particles was determined from the blue shifting of the absorption peak and found to be equal to 3.47eV indicating significant quantum confinement effect. The presence of some chemical species near the surface of ZnO was observed from FTIR analysis. Using SEM analysis, a clear change in surface morphologies of virgin ZnO as compared to ZnO-porphyrin hybrid materials was observed. The average crystallite size and structure of ZnO particles was determined with the help of XRD. From optical analysis it was investigated that even at low concentration of porphyrin at the surface of ZnO, additional bands in the external quantum efficiency spectra corresponding to Soret and Q-bands absorption can be observed. Therefore, grafting of TPPS2 porphyrin onto the surface of ZnO fine particles leads to very efficient electron injection process into the ZnO particles.