Efficient Orange Emission in Mn 2+ -Doped Cs 3 Cd 2 Cl 7 Perovskites with Excellent Stability.

Low-dimensional metal halides are attractive for applications in photodetectors, solid-state lighting, and solar cells, but poor stability is an obstacle that must be overcome in commercial applications. Herein, we successfully synthesized a Ruddlesden-Popper (RP)-phased perovskite Mn 2+ :Cs 3 Cd 2 Cl 7 with high photoluminescence quantum yield (PLQY) and outstanding thermal and environmental stability by a solvothermal method. The pristine sample Cs 3 Cd 2 Cl 7 exhibits a weak cyan broad emission centered at 510 nm with a low PLQY of ∼4%. Once Mn 2+ ions are introduced into the host lattice, a bright orange emission peaking at 580 nm with a high PLQY of ∼74% was achieved, which is attributed to the efficient energy transfer from the host to Mn 2+ ions and thus results in the 4 T 1 → 6 A 1 radiation transition of Mn 2+ ions. The photoluminescence (PL) intensity and environmental stability of Mn 2+ :Cs 3 Cd 2 Cl 7 can be further improved through A-site Rb alloying. Finally, an orange LED with outstanding color stability was fabricated on the basis of the Mn 2+ :Cs 3 Cd 2 Cl 7 . Our work successfully elucidates that dopant plays an integral role in tailoring optical properties.