Engineering interstitial Eu2+ in α-quartz creates broadband cyan emission toward full-visible-spectrum white LED lighting

Cyan-emitting inorganic phosphors capable of closing the “cyan gap” (480–520 nm) are essential for developing human-centric, full-visible-spectrum phosphor-converted white light-emitting diodes (pc-LEDs). Traditionally, these materials are created by doping activators into the standard crystallographic sites of selected hosts. Here, we report an efficient, broadband cyan-emitting phosphor SiO:Al,Eu produced by engineering interstitial activators Eu into the channel along -axis of -quartz lattice. Under 365 nm light excitation, the compound exhibits a broad cyan emission band spanning from 390 to 675 nm, with a full width of half maximum of 114 nm (4975 cm), thus effectively covering the blue-cyan-green region of visible spectrum. Additionally, it demonstrates excellent thermal stability with a high emission intensity retention of 73% at 423 K. By encapsulating the mixture of the cyan-emitting SiO:Al,Eu and a commercial orange-red phosphor on an ultraviolet ( = 365 nm) chip, a full-visible-spectrum pc-LED is successfully fabricated, showing a Commission Internationale de L'Eclairage 1931 chromaticity coordinate of (0.342, 0.359) and a high color-rendering index of 89. This study not only provides a promising cyan emitter but also inspires the future design of inorganic phosphors.