Double perovskite Cs2AgInCl6:Cr3+: broadband and near-infrared luminescent materials

Abstract

Searching for high performance and broader applications of inorganic halide perovskites has drawn extensive attention. In this work, a Cr³⁺-doped halide perovskite, Cs₂AgInCl₆:Cr³⁺, which exhibits broadband near-infrared (NIR) emission is first obtained via the traditional high temperature solid-state reaction. A broad emission band ranging from 850 to 1350 nm centered at 1010 nm with a full-width at half-maximum (FWHM) of 180 nm is assigned to the spin-allowed ⁴T₂ → ⁴A₂ transition of octahedrally coordinated Cr³⁺ ions in a very weak crystal-field environment. The excitation bands centered at 353, 565 and 800 nm can be attributed to the absorption of the Cs₂AgInCl₆ host, the Cr³⁺ d–d transitions of ⁴A₂ → ⁴T₁ and ⁴A₂ → ⁴T₂, respectively. Upon 760 nm excitation, the photoluminescence quantum yield (PLQY) of Cs₂AgIn_0.9Cl₆:0.1Cr³⁺ is about ∼22.03%. Cs₂AgInCl₆:Cr³⁺ phosphors with such broadband NIR emission have potential in phosphor converted light emitting diodes (pc-LEDs) which have applications in bioimaging and biomonitoring.