Investigating efficient energy transfer in novel strategy-obtained Gd2O2S:Dy3+, Eu3+ nanofibers endowed with white emitting and magnetic dual-functionality

Abstract

Gd2O2S:Dy3+, Eu3+ nanofibers were successfully prepared via electrospinning combined with dual-boat sulfurization approach. X-ray diffractometer analysis reveals that Gd2O2S:Dy3+, Eu3+ nanofibers possess hexagonal structure (space group: P3¯m1). The as-synthesized samples are apparently nanofibers in morphology with field emission scanning electron microscope investigation, and the average diameters of PVP/(Gd(NO3)3+Dy(NO3)3+Eu(NO3)3) electrospinning-produced nanofibers and Gd2O2S:Dy3+, Eu3+ nanofibers are 454.10 ± 4.97 nm and 162.93 ± 0.75 nm, respectively. Gd2O2S:Dy3+ nanofibers demonstrate the typical blue, yellow and weak red emission bands via the excitation of 268-nm ultraviolet. Resulted from the effective spectral overlap between Dy3+ and Eu3+, Dy3+ is proved to be the effective sensitizer for Eu3+, which leads to the energy transfer of Dy3+→Eu3+ in Gd2O2S host and improved red emission of Eu3+. Further, the mechanism of energy transfer between Dy3+ and Eu3+ is determined to be an electric doublet-electric doublet interaction. Additionally, variable fluorescent color, including blue, red and especially white, can be achieved by properly modulating the ratios between Dy3+ and Eu3+. The formation mechanism of Gd2O2S:Dy3+, Eu3+ nanofibers is also advanced. Besides, the Gd2O2S:Dy3+, Eu3+ nanofibers display paramagnetism at ambient temperature. The as-synthesized Gd2O2S:Dy3+, Eu3+ nanofibers have applicable prospects in anti-fake, lasers, modulator, liquid crystal display, drug delivery and light emitting diodes (LEDs) due to their magnetism-photoluminescence dual-functionality.