Environmentally-Friendly Europium-Based Yellow Perovskite Nanocrystals with Near-Unit Efficiency for White LED

Abstract

Recently, Mn 2+ -doped metal halide perovskites (MHPs) have been extensively studied as they can improve the photoluminescence quantum yield (PLQY) with minimal self-absorption. However, almost all of them with high efficiency are Pb/Cd-based toxic heavy metal perovskites, which seriously limits their commercial applications. To address the dual needs of high efficiency and environmental protection, this study proposes to incorporate Mn 2+ into the environmentally friendly perovskite CsEuX 3 (X = Cl/Br), and further increases PLQY to 96.9% through the codoping of Tb 3+ , which, to the best of our knowledge, is the highest reported value of all inorganic environmentally friendly perovskites in the visible light region. It is found that the codoping of Tb 3+ can reduce the host defect density and enhance the crystal field strength around Mn 2+ , acting as an energy transfer bridge. Additionally, Mn 2+ /Tb 3+ -codoped CsEuX 3 -based white lightemitting diodes (WLEDs) with a high color rendering index (Ra = 91.2) demonstrate potential for lighting applications.