Ultra‐Broadband Green‐Emitting Phosphors without Cyan Gap Based on Double‐Heterovalent Substitution Strategy for Full‐Spectrum WLED Lighting. Issue 12 (26th August 2022) - Huang, Shuai
Abstract: Phosphor‐converted white light‐emitting diodes (WLEDs) are extensively spread to every part of our daily life and trigger urgent needs for discovery of phosphors without cyan gap (spectral missing in the 480–520 nm range) in pursuit of "human‐centric" sunlight‐like full‐spectrum lighting. Here, a new ultra‐broadband green‐emitting K3 La(PO4 )2 :Eu 2+ phosphor is reported to meet this challenge. An efficient and positive double‐heterovalent substitution strategy is proved in K3 La(Ca/Sr/Ba)(PO4 )2 :Eu 2+ by the evidence of enhanced quantum yield, improved thermal stability, and the tunable luminescence color. The luminescence mechanisms are revealed in this paper. Fabricating a dichromatic 370 nm‐UV chip pumped WLED using K3 La(Ca)(PO4 )2 :Eu 2+ along with a commercially available red phosphor shows a continuity spectrum comparable to the solar spectrum with excellent CIE color coordinates of (0.350, 0.347), low color‐correlated temperature of 4853 K, and high color rendering index (Ra) of 96. It is shown that the double‐heterovalent substitution contributes to designing and optimizing phosphors for full‐spectrum WLEDs. Abstract : A series of K3 La(Ca/Sr/Ba)(PO4 )2 :Eu 2+ phosphor with tunable emission color are prepared successfully in this work, and the double‐heterovalent substitution contributes to designing and optimizing phosphors for full‐spectrum white light‐emitting diodes.