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ZnO nanoparticles with different shapes and sizes were prepared by changing coordinating ligands. Hexagonal cones presented UV and green (∼500 nm) emissions, which originated from excitons and defects, respectively. Oxygen vacancies were found to be major defects in the hexagonal cones. Blue emission at ∼440 nm was observed for hexagonal plates, and analyses of time-resolved photoluminescence spectra showed that two transitions were responsible for this blue emission, because transitions from Zni to the valence band (430 nm) and from Zni to VZn (480 nm) were distinguished by emission wavelengths and lifetimes. The visible emissions from defects were related to the roles of coordinating ligands. [ABSTRACT FROM AUTHOR]

The article discusses a study which reported the photoluminescence of gold nanoclusters encapsulated in hydroxyl-terminated fourth generation polyamidoamine dendrimers (G4-OH). Topics include an investigation of the possible existence of different types of gold nanoclusters in G4-OH(Au), a description of the ultraviolet (UV) emission intensity of the dendrimer, and details of the preparation and optical measurements.