Down-conversion and structural characterizations of trivalent terbium-doped garnet nanocrystalline phosphors for lighting applications

Nanocrystalline green-emitting Tb3+-doped Y3Al5O12 (garnet) nanophosphors were synthesized via an efficient and economical solution combustion route using hexamethylenetetramine (C6H12N4) as a fuel. The samples were synthesized at 500 degrees C and calcined at 650, 950 and 1050 degrees C for further analysis. The structural and lattice parameters for both undoped and Tb3+-doped Y3Al5O12 materials were determined by Rietveld refinement using diffraction data. The pure crystalline phase of YAG: Tb3+ having a cubic unit cell with Ia3d space group was obtained at 500 degrees C without the presence of intermediate phases like YAlO3 and Y4Al2O9 . FTIR analysis proposed the presence of different bands corresponding to AlO4 tetrahedra and AlO4 octahedra supporting the XRD measurements. The synthesis of nanocrystalline materials with slightly agglomerated particles with narrow size distribution was confirmed by transmission electron microscope (TEM). Energy dispersive X-ray (EDX) examination confirmed the synthesis of desired samples with the existence of components coordinated inside the crystalline host. The phosphors yielded bright emission in the green region owing to the D-5(4) -> F-7(5) (544 nm) transition at lambda(ex) = 267 nm. Critical distance affirmed that the transfer of energy happens by means of the multipolar association phenomenon. The down-conversion and structural investigations support the convenient utility of Y3Al5O12 : Tb (3+) materials in solidstate lighting and other optoelectronic devices.

Automated summary

Nanocrystalline green-emitting Tb3+-doped Y3Al5O12 nanophosphors were synthesized via a combustion route using hexamethylenetetramine, with structural and lattice parameters determined by diffraction data. The synthesized materials exhibited bright emission in the green region and were confirmed to have potential utility in solid-state lighting and optoelectronic devices through down-conversion and structural investigations.