Mn Doping in Low-Dimensional Perovskites: A Switch for Controlling Dopant and Host Emission

The growth of solid-state photonics relies on the designof highlyefficient devices with tunable photoluminescence (PL) based on thermallystable phosphors. In this study, a room-temperature, all-ambient synthesisof Mn-doped hybrid lead halide perovskite phosphors is presented.By applying temperature-dependent (4.2-300 K) steady-stateand transient PL measurements, the photophysical pathways of the hybridsystem were identified and the carrier recombination processes atplay were defined. At higher Mn-doping concentrations (>4%), theexcitonicwhite light host emission nearly disappears, and a bright Mn transitionappears at similar to 650 nm with a record PL quantum yield of similar to 87.4%.The intense sensitized Mn luminescence results from rapid and efficientexciton-to-dopant energy transfer, as evidenced by time-gated andfemtosecond fluorescence upconversion measurements. A millisecondPL decay time attributed to the Mn dopant and a microsecond PL decaytime associated with the excitonic emission of the host were found,indicating energy and reverse energy transfer in the system. Thesefindings provide unique insights into the chemical tailoring of theMn-dopant emission by investigating the coupling between the hostsemiconductor and the dopant ion, a stepping stone toward the developmentof high-performance solid-state light-emitting diodes and scintillators.