A novel SrLaScO4:Bi layered perovskite phosphor with broad-band green emission: Multi-cationic sites engineering, and application in high color rendering pc-WLED

In this work, a series of broad-band green phosphors SrLaScO 4 : x Bi 3+ ( x  = 0–0.1) were synthesized using the traditional solid-state method, and the luminescence was effectively enhanced via multi cationic partial substitution strategy. The SrLaScO 4 : x Bi 3+ phosphors all exhibit a wide emission band with a full width at half-maximum (FWHM) of 115–148 nm in the range of 450–700 nm upon excitation at 333 nm, effectively filling the cyan gap and peaking at 505 nm. It is proved that the observed luminescence originates from both the 3 P 1 state of Bi 3+ in [(Sr/La)O 8 ] site and the Bi 3+ - to - Sc 3+ metal to metal charge transfer (MMCT) state. The optimal concentration of Bi 3+ doped SrLaScO 4 phosphor is 1 at%, and the concentration quenching mechanism is the dipole-dipole interaction. Remarkably, the luminescence intensity of the phosphor is 198.4 % increased by partially replacing Sr 2+ ions with Mg 2+ . Due to the good matching of the excitation wavelength of the phosphor with the near-UV chip, a high-quality WLED device with color stability and high color rendering index ( Ra  = 92.1) was prepared by combining commercial phosphor with SrLaScO 4 :0.01Bi 3+ phosphor. We anticipate that this work can provide new ideas for finding high-performance phosphors for high color rendering index pc-WLED.