Preparation of red-emitting BaSiF6:Mn4+ phosphors for three-band white LEDs

Abstract BaSiF6:Mn4+ phosphors were synthesized to improve the color purity of phosphor-converted white light-emitting diodes (LEDs). The optimal synthesis conditions for attaining the brightest red emission spectrum from BaSiF6:Mn4+ were investigated. The BaSiF6:Mn4+ phosphor exhibited a strong absorption band at approximately 465 nm because of the 4A2g → 4T2g transition of Mn4+ ions. In addition, the phosphor exhibited three strong emission peaks, at 615, 632, and 650 nm, because of a combination of vibrational shifts and the 2Eg → 4A2g transition in Mn4+ ions. Thus, BaSiF6:Mn4+ is suitable for use as the red-emitting phosphor in three-band white LEDs pumped by a blue LED. The optical properties of BaSiF6:Mn4+ were examined under excitation from a commercial blue LED by coating the phosphor onto the blue LED. Similarly, a three-band white LED was also fabricated by coating the red-emitting phosphor BaSiF6:Mn4+ and green-emitting phosphor CsPbBr3 onto a commercial blue LED.