Pressure-driven Eu2+-doped K3Sc(PO4)2: A broad cyan-green emitting phosphor for closing the cyan cavity in solid-state lighting and applying in optical pressure sensor

In general, the apparent spectrum gap appearing in the cyan region (480 – 520 nm) will limit the application of the phosphor in the high-quality full-spectrum lighting. Therefore, the cyan-green emitting K3Sc(PO4)2:Eu2+ phosphor with peak at 495 nm we reported here is very essential to close the cyan gap. The cyan-green emission is caused by the highly condensed network and three different K sites for Eu2+ ions. Increasing the Eu2+ ions content causes the spectral tuning from 468 nm to 497 nm. K3Sc(PO4)2:0.05Eu2+ exhibits excellent thermal stability: the integrated intensity at 423 K are still 90.0% of initial intensity. The red shift with shift rate of 7.9 cm−1/kbar of the K3Sc(PO4)2:Eu2+ induced by pressure indicates that the phosphor has a good application prospect in optical pressure sensor. At ambient pressure, the identical profile and position of the normalized PL spectra in the compression and decompression process confirm the good structural rigidity and stability of the K3Sc(PO4)2. The color rendering index (Ra) and correlated color temperature (CCT) of the WLEDs devices under 50–500 mA working current are still maintain stable (Ra of 87.5 and CCT of 4505 K). These suggest the broad cyan-green emitting phosphor plays an important role in closing the cyan cavity of solid-state lighting and applying in optical pressure sensor.