Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy3+,Tb3+,Eu3+ phosphors

Abstract

A series of Dy³⁺, Tb³⁺, Eu³⁺ singly or doubly or triply doped GdF₃ phosphors were synthesized by a glutamic acid assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure GdF₃. The obtained samples have a peanut-like morphology with a diameter of about 270 nm and a length of about 600 nm. Under UV excitation, GdF₃:Dy³⁺, GdF₃:Tb³⁺ and GdF₃:Eu³⁺ samples exhibit strong blue, green and red emissions, respectively. By adjusting their relative doping concentrations in the GdF₃ host, the different color hues of green and red light are obtained by co-doped Dy³⁺, Tb³⁺ and Tb³⁺, Eu³⁺ ions in the GdF₃ host, respectively. Besides, there exist two energy transfer pairs in the GdF₃ host: (1) Dy³⁺ → Tb³⁺ and (2) Tb³⁺ → Eu³⁺. More significantly, in the Dy³⁺, Tb³⁺, and Eu³⁺ tri-doped GdF₃ phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of Eu³⁺. In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K) and low temperature (2 K). It is obvious that multifunctional Dy³⁺, Tb³⁺, Eu³⁺ tri-doped GdF₃ materials including tunable multicolors and intrinsic paramagnetic properties may have potential applications in the field of full-color displays.