An Efficient Broadband Cyan Phosphor for Full‐Spectrum pc‐WLEDs

AbstractCurrent phosphor‐converted white light‐emitting diodes (WLEDs) exhibit an unexpected gap in the cyan spectral range (480–520 nm), which hinders the realization of high color rendering index (CRI > 90) at high correlated color temperatures (CCT > 4500 K). To address this issue, the existing cyan phosphors have to be blended with at least two phosphors (yellow and red) for producing full‐spectrum WLEDs, which, however, mostly offer luminous efficiencies below 100 lm W−1 for high CRI at high CCT. In this work, a broadband cyan Lu2SrAl2Ga2SiO12: Ce3+ garnet phosphor is developed by shifting the efficient green emission of Lu2SrAl4SiO12: Ce3+ toward the blue side via 2Ga3+ substitution for 2Al3+. The new cyan phosphor shows an emission band peaked at 489 nm with a bandwidth of 80 nm and internal/external quantum efficiencies of 81%/63%. More crucially, the new phosphor can be used to produce full‐spectrum pc‐WLEDs via blending with only a red phosphor. By adjusting the cyan/red phosphor ratio, full‐spectrum pc‐WLEDs with tunable CCT ranging from 3500 to 6837 K and simultaneous high CRI (>90) and high luminous efficiencies (113.7–127.3 lm W−1) are achieved. This research furnishes a promising cyan phosphor for applications in efficient full‐spectrum LED lighting.