Morphology Tailoring of ZnWO Crystallites/Architectures and Photoluminescence of the Doped RE Ions (RE = Sm, Eu, Tb, and Dy).

Tartrate (Tar) was originally employed in this work as a chelating/structure-directing agent for hydrothermal crystallization of ZnWO, where the decisive roles of Tar/Zn/WO molar ratio, solution pH (7-10), and the use of ethylene glycol (EG) cosolvent in phase/morphology evolution were deciphered in detail. It was unambiguously manifested that Tar may remarkably retard the intrinsically preferred [001] growth of ZnWO, transform 1D nanorods to 0D nanoparticles and then to 2D platelets, and meanwhile induce face-to-face alignment of the platelets to form spheroidal, ellipsoidal and snowflakelike 3D architectures, where the 2D crystallites were revealed to develop via oriented attachment (colattice) of non-(00) facets. A lower solution pH and excessive WO were clearly shown to enhance and offset the effect of Tar, which led to ellipsoidal assemblies of substantially larger 2D crystallites and suppressed 2D growth/3D assembly of ZnWO crystallites, respectively. With the spheroidal architectures for example, doping ZnWO with RE yielded (ZnRE)WO phosphors (RE = Sm, Eu, Tb, and Dy, respectively) that show luminescence overlapped from the typical linelike and broad-band (∼350-700 nm) emissions of RE and WO, respectively. The luminescence color of the sample was found to drift away from the blue corner of the CIE chromaticity diagram with RE doping and to be dependent on the type of RE.