Novel white light emitting dysprosium oxalate nanocrystals: Competing luminescence quenching by the features of Dy-Oxalate layered structure

Novel white light emitting dysprosium oxalate nanocrystals were prepared via microwave assisted co-precipitation method and the photoluminescence characteristics were elucidated on the basis of crystal structure. X-ray powder diffraction and transmission electron microscopy analyses were employed to identify the structure and morphology of the synthesized nanocrystals. Under 364 nm excitation dysprosium oxalate nanocrystals emit blue (480 nm), yellow (572 nm) and red (655 nm) light with chromaticity co-ordinate (0.35, 0.39) which lies in the near white light region. The efficient luminescence exhibited by dysprosium oxalate negating the probable luminescence limiting factors is further investigated by single crystal structure analysis. The crystal structure of dysprosium oxalate facilitates well separated Dy3+ centres thereby minimizing the energy migration between the luminescent centres, allowing higher concentration of Dy3+ ions in oxalate matrix without substantial luminescence quenching. The other crystallographic features promoting the luminescence emission of Dy3+ in oxalate matrix are also discussed in detail in view of the structural features.