Solvothermal synthesis and characterization of blue, green and red emitting Y2O3:Ln3+ (Ln3+ = Tm3+, Tb3+ and Eu3+) nanocrystals

Abstract

Lanthanide ions (Tm3+, Tb3+ and Eu3+) doped Y2O3 nanocrystals were prepared via solvothermal refluxing calcination method. Yttrium chloride hexahydrate and rare earth chloride (TmCl3, TbCl3 and EuCl3) were used as starting materials for the preparation of co-precipitated gel. The organic solvents such as ethylene glycol and polyethylene glycol (200#) were used to reflux co-precipitated gel and solvothermal refluxing reaction was carried out at 180°C (ethylene glycol) and 240°C (polyethylene glycol 200#) for 4 h. The samples were calcined at 800°C and 1000°C for 5 h to convert precursor materials into Y2O3 nanocrystals. The structure, morphology and thermal stability were characterized by XRD, TEM, FESEM, and TG-DTA analysis. The as prepared materials exhibited agglomerated and sphere like morphology with 20-30 nm in diameter depending on refluxing solvents used in the synthesis. The calcined samples after solvothermal reaction in polyethylene glycol exhibited sphere morphology with 30-80 nm in diameter. The photoluminescence results of Tm3+, Tb3+ and Eu3+ doped Y2O3 nanocrystals showed strong blue, green and red emission around 450, 540 and 610 nm under the excitation wavelength of 360, 304 and 254 nm respectively. The PL results were compared with reference sample prepared via co-precipitated calcination method.