Aerosol Synthesis of Gd2O3:Eu/Bi Nanophosphor for Preparation of Photofunctional Pearl Pigment as Security Material

Gd 2 O 3 :Eu/Bi nanoparticles were synthesized via spray pyrolysis and applied for the preparation of a luminescent pearl pigment as an anti-counterfeiting material.The luminescence properties were optimized by changing the Eu 3+ and Bi 3+ concentration.Ethylene glycol was used as an organic additive to prepare the Gd 2 O 3 :Eu/Bi nanoparticles.The highest emission intensity was achieved when the total dopant content was 10.0 at.% and the mole fraction of Bi was 0.1.The concentration quenching was mainly due to dipole-dipole interactions between the same activators, and the critical distances were 9.0 and 19.6 Å for Eu 3+ and Bi 3+ , respectively.The prepared Gd 2 O 3 :Eu/Bi powder exhibited an average size of approximately 82.5 nm and a narrow size distribution.Finally, the Gd 2 O 3 :Eu/Bi nanophosphor coated on the surface of the pearl pigment was confirmed to have good red emission under irradiation from a portable ultraviolet light-emitting diode lamp (365 nm).