Defect-induced deep red luminescence of CaGdAlO 4 -type layered perovskites: multi-cationic sites partial/full substitution and application in pc-LED and plant lighting.

A series of CaGdAlO 4 -type layered perovskite phosphors showing deep red luminescence ( λ em = 711 nm, λ ex = 338 nm) were synthesized via a solid-state reaction. A comprehensive analysis performed via photoluminescence, X-ray photoelectron spectroscopy, thermoluminescence, and fluorescence decay revealed that the deep red luminescence is related to oxygen defects and particularly oxygen interstitials. The defect-related luminescence was effectively regulated through partial substitution of multi-cationic sites (the Ca 2+ site with Mg 2+ , Sr 2+ , and Ba 2+ ; the Gd 3+ site with La 3+ , Y 3+ , and Lu 3+ ) and full substitution of Gd 3+ with Y 3+ . Remarkably, a 383.3% stronger luminescence was obtained through partial substitution with Lu 3+ , and the quantum yield of luminescence reached 28.74%, which is higher than those values of most previously reported self-luminescent systems. A pc-LED device was fabricated using this phosphor, and the device was shown to have potential application in indoor plant cultivation.