Double perovskite Ca2GdNbO6:Mn4+ deep red phosphor: Potential application for warm W-LEDs

Abstract A novel Mn 4+ -doped Ca 2 GdNbO 6 (CGN) phosphor was prepared by high-temperature solid-state reaction. The crystal structure was investigated by X-ray diffraction patterns and unit cell structure. Mn 4+ replaced the location of Nb 5+ in the CGN lattice, and the value of energy gap ( E gap ) decreased from 2.16 eV to 1.13 eV, indicating that Mn 4+ ions play a great influence on the absorption of CGN hosts. The broad excitation band from 250 nm to 550 nm matches well with commercial near-UV light emitting diodes, and the emission peak centered at 680 nm is due to 2 E→ 4 A 2g transition in Mn 4+ ions. The CIE chromaticity coordinates (0.698, 0.303) of CGN:Mn 4+ phosphor was close to standard red color coordinates (0.666, 0.333). These investigations demonstrate CGN:Mn 4+ phosphor as an efficient red phosphor for potential applications.