Role of octahedral deformation in the broad-band emission in Mn-doped lead halide perovskite: First-principles investigation for the case of CsPbX3 (X = Cl, Br, I)

Doping manganese ions (Mn2+) in lead halide perovskites (LHPs) has been proven to be an efficient strategy to achieve excellent light-emitting performance. A self-trapped exciton on a MnX6 (X = Cl, Br, I) octahedron and associated energy transfer play critical roles in the broad-band emission of Mn-doped LHPs. In this work, we performed first-principles study on the effect of octahedral MnX6 deformation on the light emission in Mn-doped LHPs. It is revealed that the broad-band luminescence peak is associated with Mn 3d orbitals. Our results revealed that octahedral MnX6 deformation, which enhances the dispersion of the associated bands, plays an important role in the broad-band emission in Mn-doped LHPs. Furthermore, octahedral MnX6 deformation shows dependence on the halogen element and structural phase of LHPs. Our results proved that tuning octahedral MnX6 deformation is an efficient way to achieve the regulation of the luminescence performance of Mn-doped LHPs. Our predictive results may inspire further studies on the applications of doped Mn perovskites.