Abnormal variation in the host bandgap of Mn-doped perovskite CsPbCl3

Mn-doped halide perovskites as light-emitting materials have exhibited outstanding performance. However, the influence of Mn concentration on the luminescence performance is unclear. Herein we performed a theoretical study on the effect of Mn concentration on the luminescence behavior of Mn-doped perovskite CsPbCl3. The results revealed an abnormal variation in the host photoluminescence peak, corresponding to bandgap transition of host CsPbCl3, with Mn concentration. The host bandgap shows a blue-shift first and a subsequent red-shift with increasing Mn concentration. Our theoretical analysis proved that the blue-shift in the host photoluminescence peak is attributed to the reduced antibonding between Pb s and Cl p orbitals atoms by Mn substituting Pb. The subsequent red-shift results from the shortened Pb-Cl bonds, pushing up the Pb s-Cl p antibonding states. Our work provides a further insight into the fundamental strategy of Mn doping for improving luminescence performance in perovskite-based light-emitting devices.