Crystal-Site Engineering of Novel Na 3 KMg 7 (PO 4 ) 6- x (BO 3 ) x :Eu 2+ Phosphors for Full-Spectrum Lighting

The "cyan gap" is the bottleneck problem in violet-driven full-spectrum white-light-emitting diodes (wLEDs) in healthy lighting. Accordingly, we develop a novel broadband-blue-cyan emission Na KMg (PO ) (BO ) :Eu (NKMPB:Eu ) phosphor via crystal-site engineering. This phosphor is derived from the Na KMg (PO ) :Eu phosphor, which shows desired abundant cyan emissive components. A comparative study is conducted to reveal the microstructure-property relationship and the key influential factors to its spectrum distribution. It can be found that the introduced (BO ) units can manipulate the site-selective occupation of Eu activators, asymmetrically broadening the emission spectrum in NKMPB:Eu . Considering detailed luminescence performance analysis and the density functional theory calculations, a new substitution pathway of Eu is created by substituting (PO ) with (BO ) units, making partial Eu ions enter the Mg (CN = 5, CN = 6) crystallographic sites, and yielding an extra emission band at 600 nm (16667 cm ) and especially 501 nm (19960 cm ). Meanwhile, a high-color-quality full-spectrum-emitting wLEDs was fabricated, upon 100 mA forward-bias current driven. Due to the achieved extra cyan emissive components of NKMPB:Eu , the constructed NKMPB:Eu -based wLEDs show better color rendering ability (∼90.9) than that of Na KMg (PO ) :Eu -based wLEDs (∼86.3), and also demonstrate its great potential in full-spectrum healthy lighting.