Efficient Orange Emission in Mn2+-Doped Cs3Cd2Cl7 Perovskites with Excellent Stability

Abstract

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 Mn²⁺:Cs₃Cd₂Cl₇ with high photoluminescence quantum yield (PLQY) and outstanding thermal and environmental stability by a solvothermal method. The pristine sample Cs₃Cd₂Cl₇ exhibits a weak cyan broad emission centered at 510 nm with a low PLQY of ∼4%. Once Mn²⁺ 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 Mn²⁺ ions and thus results in the ⁴T₁ → ⁶A₁ radiation transition of Mn²⁺ ions. The photoluminescence (PL) intensity and environmental stability of Mn²⁺:Cs₃Cd₂Cl₇ can be further improved through A-site Rb alloying. Finally, an orange LED with outstanding color stability was fabricated on the basis of the Mn²⁺:Cs₃Cd₂Cl₇. Our work successfully elucidates that dopant plays an integral role in tailoring optical properties.