Ultraviolet C upconversion fluorescence of trivalent erbium in BaGd2ZnO5 phosphor excited by a visible commercial light-emitting diode.

Multiple ultraviolet (UV) emission bands have been obtained in Er3+ doped BaGd2ZnO5 phosphor under the excitation of a 532 nm solid-state laser, and the emission peaks at 217, 254, 278, 296, 314, 348, 374 and 394 nm were determined to stem from the high-energy states 4D(1/2), 4D(7/2), 2H(9/2), 2P(1/2), 2P(3/2), 4G(7/2), 4G(11/2), 4H(9/2) of trivalent erbium, respectively. Some UV emission bands in the UVC region can be observed when the sample was excited by commercial green (529 nm) and blue (460 nm) LED. In view of the small size, low-drive voltage and price of LED, UVC upconversion phosphor BaGd2ZnO5:Er3+ excited by visible LED has potential application in environmental sciences.