Predicting Thermal Quenching in Inorganic Phosphors

Abstract

Phosphor-converted light emitting diodes (LEDs) are a highly efficient form of solid-state lighting. A key performance metric of a phosphor is its thermal quenching (TQ), which is the percentage loss of emission at elevated temperatures during operation. In this work, we unify the two prevailing theories—the crossover and thermal ionization mechanisms—into a single predictive model for TQ. Using ab initio molecular dynamics (AIMD) simulations, we demonstrate for the first time that TQ under the crossover mechanism is related to the local environment stability of the activator. Further, by accounting for the effect of the crystal field on the thermal ionization barrier, we show that a unified model can predict the experimental TQ in 29 known phosphors to within a root-mean-square error of ∼3.1–7.6%. Finally, we propose an efficient topological approach to rapidly screen vast chemical spaces for the discovery of novel, thermally robust phosphors.