Light emission due to energy transfer from Gd3+ to Eu 3+ ions in paramagnetic NaGdF4: Eu3+ submicrometer disks

The paramagnetic NaGdF4: Eu3+ submicrometer disks exhibit a red emission under the excitation of UV light and a low voltage electron beam. The energy transfer from the Gd3+ to Eu3+ ions in NaGdF4: Eu3+ becomes less efficient with increasing Eu3+ doping concentration, which can be used to adjust the relative intensity of emission excited at 394 and 273 nm. The energy transfer process is less efficient at 10 K than at room temperature, which might be due to the existence of trap states that hampers the energy migration at low temperature. The cathodoluminescence (CL) spectrum and the image of NaGdF 4: Eu3+ are reported, and the CL mechanism is discussed. This multifunctional material with a uniform disk morphology may be potentially applied in lighting, field emission display, and magnetic resonance imaging.