Constructing a single-white-light emission by finely modulating the occupancy of luminescence centers in europium-doped (Ca1−xSrx)9Bi(PO4)7 for WLEDs

Abstract

Nowadays, phosphor-converted white light-emitting diodes (WLEDs) have drawn great attention in the field of lighting. The most currently used method combining a blue LED chip with a yellow YAG:Ce phosphor suffers from a high correlated color temperature (CCT) and low color rendering index (CRI) due to the deficiency of red emission. For achieving white light with a higher quality, the additional red component should be supplemented in the emission spectrum. In this study, we propose a design strategy to construct a single-white-light-emitting phosphor by modification of the spectrum based on structural evolution. After the introduction of strontium into a multi-cation site Ca₉Bi(PO₄)₇:Eu phosphor and finely modulating the occupancy of the luminescence centers, tunable emission with band broadening and a red-shift was realized. Moreover, warm white light with an Ra of 87 and CCT of 3383 K was obtained based on the (Ca_1−xSr_x)₉Bi(PO₄)₇:Eu single phosphor, which suggests its good potential in WLED applications.