Multicolor photoluminescence and energy transfer properties of dysprosium and europium-doped Gd2O3 phosphors

In this study, a series of Gd2O3: Ln(3+) (Ln = Dy, Eu) submicrospheres were successfully prepared by a hydrothermal method and a subsequent higher temperature pyrolysis. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectrometer (EDS), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM) were utilized to characterize the as-prepared samples. The precursor sample thoroughly decomposed into Gd2O3 submicrospheres with a diameter of about 550 nm after calcination. Under UV excitation, the samples exhibit multicolor emissions including yellow-green, yellow, red as well as white, moreover, the Dy3+ ions acted as donors can transfer the energy to Eu3+ served as acceptors in Gd2O3: Dy3+, Eu3+ system. The interaction between Dy3+ ions and Eu3+ ions is verified to be phonon-assisted electric quadrupole-quadrupole interaction. Multicolor luminescence including white light emission can be obtained through varying the content of Eu3+ or adopting different excitation wavelengths in Dy3+ and Eu3+ co-doped Gd2O3 system. The energy transfer efficiency reaches 88.2% when the doped concentration of Eu3+ is 0.035. The CIE chromaticity diagram directly reveals the variability of the hue of the as-prepared samples. Besides, the as-prepared samples exhibit paramagnetic properties at room temperature. This type of color-tunable luminescence phosphors has promising applications in the fields of photoelectronic devices and biomedical science. (C) 2015 Published by Elsevier B.V.