Unveiling Mn<sup>2+</sup> Dopant States in Two-Dimensional Halide Perovskite toward Highly Efficient Photoluminescence
Binbin Su, Мaxim S. Моlokeev, Zhiguo Xia
Abstract
Doping is able to create novel optoelectronic properties of halide perovskites, and the involved mechanism of efficient emission is still a challenge. Herein Mn2+ substitution into 2D layered perovskites (C8H20N2)PbBr4 was investigated, demonstrating broad-band orange-red emission originating from the 4T1 → 6A1 transition of Mn2+ dopant. The photoluminescence quantum yield (PLQY) of Mn2+ emission is up to 60.8% related to the energy transfer in coupled states. We verify that an actual Mn2+ dopant as low as 0.476% reaches a high PLQY, whereas the nominal adding amount is 0.8 as the Mn2+/Pb2+ ratio. The small activation energy (∼6.72 meV) between the Mn2+ d state and the trap state accounts for this highly efficient energy transfer and photoluminescence. The proposed luminescence mechanism in Mn2+-doped 2D halide perovskites would provide unique insights into the doping design toward high-performance luminescence materials.