Facile fabrication of thermal stable Eu(HCOO)3 red-emitting crystals with high color purity for near-ultraviolet chip triggered white light-emitting diodes

Abstract The thermal stable Eu(HCOO)3 red-emitting crystals were synthesized by a facile hydrothermal route. Both excitation and emission spectra revealed that the prepared crystals can be efficiently pumped by the near-ultraviolet (NUV) light and it can emit brightness red light with admirable color purity of 90.4%. With the help of Judd-Ofelt theory, the optical transition intensity parameters of Eu3+ ions were evaluated so as to explore its local symmetry performance in the Eu(HCOO)3 host lattices. The thermal quenching behaviors of the studied samples were investigated through the temperature-dependent emission spectra. Ultimately, a white light-emitting diode (WLED) lamp with good color rendering index (78.2) and correlated color temperature (6386 K) was packaged through coating the tricolor phosphors (BaMgAl10O7:Eu2+ blue-emitting phosphor, (Ba,Sr)2SiO4:Eu2+ green-emitting phosphor and resultant red-emitting crystals) onto the surface of a NUV chip. These results disclosed the high brightness Eu(HCOO)3 red-emitting crystals were suitable for NUV chip triggered WLED applications.