Narrow-band red emitting phosphor BaTiF6:Mn4+: preparation, characterization and application for warm white LED devices
As a new class of non-rare-earth red phosphors for high-efficiency warm white light-emitting diodes (white LEDs), Mn4+ ion activated fluoride compounds have been extensively investigated recently and hold the potential to supersede commercial rare earth doped nitride phosphors. Herein, a series of Mn4+ ions doped BaTiF6 phosphors have been prepared via the hydrothermal route using citric acid as a surfactant. After a systematic investigation, we illustrate the effects of reaction time, nominal concentration of HF solution, and reaction temperature on the luminescence performance of the phosphor. The BaTiF6:Mn4+ phosphor generates narrow red emission, which is highly perceived by the human eyes and leads to excellent chromatic saturation of red emission spectra. Simultaneously, concentration and thermal quenching are investigated systematically, and the quenching mechanisms are elucidated in detail. Employing BaTiF6:Mn4+ as a red phosphor, we fabricate a high-performance white LED with low correlated color temperature of 3974 K, high color rendering index of 90.6 and luminous efficacy of 132.54 lm W−1. Based on the improvement in correlated color temperature and color rendering index, the BaTiF6:Mn4+ red phosphor supplements the deficiency of LEDs fabricated by combining blue chips and only YAG:Ce3+, which suggests that it is a promising commercial red phosphor in warm white LEDs.