Energy Transfer from Pr 3+ to Gd 3+ and Upconversion Photoluminescence Properties of Y 7 O 6 F 9 :Pr 3+ , Gd 3 .

Upconversion materials have numerous potential applications in light energy utilization due to their unique optical properties. The use of visible light excitation to obtain ultraviolet emission is a promising technology with broad application prospects, while relevant research is absent. A series of Pr 3+ , Gd 3+ doped Y 7 O 6 F 9 phosphors were synthesized by traditional solid-state reaction. X-ray diffraction, scanning electronic microscopy, steady-state photoluminescence spectra, a decay dynamic, and upconversion emission spectra of the samples were studied. Under the excitation of 238 nm, the energy transfer from Pr 3+ to Gd 3+ was realized and a strong ultraviolet B emission due to the 6 P 7/2 → 8 S 7/2 transition of the Gd 3+ ions was achieved. Under the excitation of a 450 nm blue laser, Pr 3+ absorbed two blue photons to realize the upconversion process and then transferred the energy to Gd 3+ to obtain the ultraviolet B emission.