Efficient violet-light-excitable blue-cyan phosphor for full-spectrum lighting

Abstract

In order to realize full-spectrum lighting, excellent blue-cyan phosphors, which can be excited by violet LED chips, are particularly important to compensate for the spectral cyan gap. Herein, we report an efficient and thermally stable Eu²⁺-doped T-phase blue-cyan phosphor, Ba_1.305Ca_0.38Mg_0.3SiO₄:0.015Eu²⁺ (BCM_0.3S:Eu²⁺) through structure design and composition optimization. The emission spectrum presents an asymmetric band peaking at 475 nm with a small Stokes shift under 400 nm excitation. The internal/external quantum efficiencies of this phosphor are up to 82.9%/66.2%, and the integrated emission intensity at 150 °C is maintained at 90% of that at room temperature. Due to the compensation of the blue-cyan gap, the fabricated white light-emitting diode (pc-WLED), made of BCM_0.3S:Eu²⁺ combined with the 400 nm chip and other phosphors, shows an ultra-high color rendering index (R_a = 95.7). These prominent properties give BCM_0.3S:Eu²⁺ potential applications in the field of full-spectrum healthy lighting.