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

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.