Solid-state synthesis of pure and doped lanthanide oxide nanomaterials by using polymer templates. Study of their luminescent properties

Abstract

We herein reports the solid-state synthesis of pure and doped lanthanide oxides by using polymeric materials (chitosan and polystyrene-co-poly(4-vinylpyridine), PS-co-P4VP) as a solid template. Lanthanide nanomaterials are prepared in two-step methodology combining both solution and solid procedures. The first involves the synthesis of macromolecular complexes Chitosan.[M(NO3)(3)//M'(NO3)(3)] and PS-co-P4VP.[M(NO3)(3)//M'(NO3)(3)] (M = La, Pr; M' = Eu); and the second consists in the pyrolysis at 800 degrees C of the as-prepared solid macromolecular complexes. The pyrolytic products were characterized by X-ray diffraction, SEM-EDS, TEM, and HR-TEM. Whereas similar particle size distribution in average (ca. 25 nm) was observed with both polymer templates, a higher degree of crystallinity was obtained by using PS-co-P4VP. Importantly, the emission luminescent intensity of the doped pyrolytic oxides, La2O3//Eu2O3 and PrO1,83//Eu2O3, is not quenched despite the presence of dopant. Thus, the as-prepared doped oxides exhibit an enhanced Eu3+ emission originated from the D-5(0) -> F-7(n) (n = 1, 2, 3, 4) transitions, which is more intense for the PS-co-P4VP template. This synthetic methodology base on the pyrolysis of polymeric complexes can be considered as a general and straightforward methodology leading to pure and Eu3+-doped nanostructured lanthanide oxide.