Broadband NIR Garnet Phosphors with Improved Thermal Stability via Energy Transfer

Abstract

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have attracted more and more attention because of their many potential optical applications. However, high-performance broadband NIR phosphors are still rare. Here, we demonstrated that Cr3+-to-Yb3+ energy transfer (ET) is an effective strategy to boost the properties of NIR luminescence materials in Ca2LaZr2Ga2.8Al0.2O12: Cr3+,Yb3+ (CZGG: Cr3+, Yb3+). In addition to the enrichment of short-wave NIR emission in 900–1100 nm, the overall thermal stability of CZGG: Cr3+, Yb3+ can be improved by leveraging high-efficiency ET from Cr3+ to Yb3+, ascribed to the fast ET from Cr3+ to its nearest Yb3+ as well as the superior thermal stability of Yb3+. Additionally, an NIR pc-LED device was packaged via combining CZGG: Cr3+, Yb3+ with a blue LED chip to demonstrate its possible application in compact nonvisible light sources.