Mn2+ as an "Optical Energy Shutter" to Regulate Red‐to‐NIR Luminescence in Rare Earth Doped Layered Quadruple Perovskites.

Metal halide perovskites (MHPs) have shown great application prospects in the field of optoelectronics owing to their superior optical and optoelectronic properties. Bandgap engineering and impurity doping are effective ways to achieve regulation of luminous properties in the visible light region. However, realizing efficient deep red and wide‐range tunable near‐infrared (NIR) emission remains a challenge. Here, a series of rare earth (RE3+) ions (RE = Nd, Dy, Ho, Er, Tm, Yb) doped Cs4Cd1−xMnxSb2Cl12 (0 ≤ x ≤ 1) quadruple perovskites are designed. An efficient tunable luminescence from red to NIR light is achieved based on the energy transfer (ET) from Mn2+ to RE3+ by building the Mn2+ energy bridge, which covers the NIR‐I (650–900 nm) and NIR‐II (900–1700 nm) regions. Moreover, the ET efficiency is availably influenced by the doping concentration of Mn2+. Interestingly, the energy bridge from Mn2+ to RE3+ is cut off because of the increased bandgap when Bi3+ is introduced into the RE3+‐doped Cs4Cd0.4Mn0.6Sb2−yBiyCl12 (0 ≤ y ≤ 2) lattice. Through bandgap engineering, the ET from Mn2+ to RE3+ resembles an "optical energy shutter" which quenches the NIR emission of RE3+ owing to the mismatched energy level but enhances the emission of Mn2+. [ABSTRACT FROM AUTHOR]