Enhancing Photoluminescence and Stability of Mn-Doped Cs2InCl5.H2O Microcrystals with Introduced Bi3+ Ion

In this work, lead-free zero-dimensional (0D) all-inorganic perovskite Mn2+-doped Cs2InCl5.H2O microcrystals (MCs) with introduced Bi3+ ion were synthesized by supersaturation recrystallization at room temperature. The electronic bandgap of the MCs is tuned from similar to 5.1 to similar to 3.1 eV, and the electronic absorption is enhanced in the 200-400 nm region by Bi3+ incorporation. Upon excitation at 365 nm, the MCs with introduced Bi3+ exhibit strong red emission peaking at 640 nm, which is attributed to the Mn2+ transition (T-4(1g) ? (6)A(1g)). Simultaneous Mn2+ and Bi3+ incorporation into Cs2InCl5.H2O shows 60 times enhancement of the 640 nm emission band compared to Mn2+ alone. This PL enhancement is attributed to the energy transfer (ET) from the [BiCl6](3-) octahedron, which acts as a UV light absorber and exciton donor, to [MnCl6](4-). In addition, a yellow-light -emitting diode (LED) device based on the Cs2In0.45Bi0.55Cl5.H2O:17%Mn MCs was fabricated and evaluated, showing high color saturation at a drive current of 420 mA and good stability. This study demonstrates a new method for achieving efficient red emission by incorporating ns(2) metal ions and Mn ions in 0D lead-free metal halides.