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

Gd2O3: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 Eu3+ and Bi3+ concentration. Ethylene glycol was used as an organic additive to prepare the Gd2O3: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 Eu3+ and Bi3+, respectively. The prepared Gd2O3:Eu/Bi powder exhibited an average size of approximately 82.5 nm and a narrow size distribution. Finally, the Gd2O3: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). Key words: Spray pyrolysis, Nanophosphor, Pearl pigment, Anti-counterfeiting