Abnormal spectral broadening of ordered-structure near-infrared phosphor La2CaHfO6:Cr3+

Abstract

Near-infrared (NIR) phosphors play a key role in the preparation of NIR phosphor-converted light-emitting diodes (NIR pc-LEDs) for night vision, sensing and non-destructive detection, but how to search for broadband NIR phosphors still remains a big challenge. In this work, we obtained an abnormal broadband NIR emission in La₂CaHfO₆:Cr³⁺ with an ordered structure. It shows an emission maximum of 906 nm and a large full width at half-maximum (FWHM) of 276 nm. An empirical rule for discovering broadband NIR phosphors with double perovskite structures was suggested by considering their structural parameters, which helped to find La₂CaSnO₆:Cr³⁺ and LaCa₂NbO₆:Cr³⁺ with FWHM values of 280 and 290 nm. This work provides an interesting perspective for developing NIR phosphors with double perovskite structures.