Preparation and luminescence performance of Li2ZnGeO4: Dy3+, Eu3+ phosphors for white LEDs

Li 2 ZnGeO 4 : Dy 3+ , Eu 3+ phosphors were successfully synthesized by solid-state reaction. The phosphor samples exhibited high-quality white light emission under 391 nm excitation. The optimal doping concentration of Eu 3+ in Li 2 ZnGeO 4 : Dy 3+ , Eu 3+ phosphors is 0.3%. Subsequently, as the doping concentration of Eu 3+ increases, a concentration quenching phenomenon occurs. The internal quantum efficiency of Li 2 ZnGeO 4 : 0.2Dy 3+ , 0.2Eu 3+ phosphor is 37.7%. Within the temperature range of 423K to 473K, Li 2 ZnGeO 4 :0.2Dy 3+ ,0.2Eu 3+ phosphors exhibit excellent thermal stability, with a thermal quenching activation energy of 0.2472 eV. The luminous intensity at 423 K can be maintained at more than 76.0% of the room temperature. The synthetic Li 2 ZnGeO 4 : Dy 3+ , Eu 3+ phosphors were combined and packaged with 387 nm ultraviolet chips to fabricate LED devices. Under the drive of current, they emitted bright white light with a color rendering index Ra of 80.7. When the current varies from 20 mA to 220 mA, the emission spectrum intensifies, indicating the stable illumination characteristics of the prepared Li 2 ZnGeO 4 : Dy 3+ , Eu 3+ phosphors. The characteristic of spectral stability enhancement under high current meets the high-load working requirements of lighting appliances and provides material support for the upgrading of related electrical appliances.