A novel High-Efficiency cyan phosphor for Human-Centric lighting with 410 nm excited white LEDs

[Display omitted] •A strategy for producing cyan phosphors for 410 nm chips by crystal field engineering was presented.•CaSrLu4O8:Ce3+ exhibits high quantum efficiency and high thermal stability.•Phosphor is suitable for 410 nm commercial chips.•Phosphor can fill the cyan gap and achieve full-spectrum lighting. Although cyan (470–510 nm) phosphors that can be efficiently excited by the 410 nm purple-blue chip is of great importance to achieve human-centric full-spectrum lighting, there is still a lack of such highly efficient luminescent materials at present. Herein, we developed a novel cyan phosphor that effectively addresses the aforementioned needs. By employing crystal field engineering to modulate emission, spectral changes in emission were achieved by substituting Sr2+ with Ca2+ or Ba2+ in Sr2Lu4O8:Ce3+. Among them, the Ca2+-substituted phosphors cause the [LuO6] sites shrink, increasing the crystal-field strength and resulting in a red-shift. As a result, CaSrLu4O8:0.01Ce3+ exhibits main emission in the range of 470–510 nm with high internal/external quantum efficiency reaching 91.23 %/56.62 %, and its luminescence intensity at 423 K still maintains about 80 % of that at room temperature. More importantly, the CaSrLu4O8:0.01Ce3+ can be effectively excited by the 410 nm chip. Finally, white LEDs based on the 410nm N-UV chip were packaged with the as-prepared cyan phosphor CSLO:0.01Ce3+ and achieved high color rendering index (Ra = 96.4). In addition to providing a well-performing cyan phosphor, this study paves the way for the discovery of other phosphors by crystal-field engineering.