Efficient Mn<sup>2+</sup> Doping in Non-Stoichiometric Cesium Lead Bromide Perovskite Quantum Dots
Lamia Hidayatova, Chenjia Mi, Novruz G. Akhmedov, Yuan Liu, Arjumand K. Shafiq, Hadi Afshari, Nishya Mohamed‐Raseek, Dilruba A. Popy, Sisi Xiang, Yi‐Chen Chen, Bayrammurad Saparov, John W. Peters, Dmitri V. Talapin, Bin Chen, Madalina Furis, E. R. Glaser, Yitong Dong
Abstract
High Resolution Image Download MS PowerPoint Slide Doping magnetic transition metal ions (e.g., Mn 2+ ) into colloidal quantum dots endows novel optical and magnetic properties to the host materials. CsPbBr 3 quantum dots (QDs) are emerging light-emitting materials with high structural and chemical flexibility in the visible spectral regime. However, efficiently doping Mn 2+ ions in CsPbBr 3 QDs remains challenging, especially when size confinement and ensemble uniformity are needed for understanding the underexplored exciton-dopant exchange interaction. Here, we introduce a doping mechanism based on electrostatic surface Mn 2+ adsorption that enables efficient Mn 2+ incorporation in strongly confined CsPbBr 3 QDs. The resultant QDs are found to have a Cs-deficient stoichiometry compared to their undoped counterparts. A redox reaction-based purification method was developed to remove Mn 2+ cations that are tightly adsorbed on the surface to determine the concentration of lattice-incorporated Mn 2+ . Our synthesis enables a Mn 2+ doping/alloying concentration of up to ∼44% with a Mn 2+ photoluminescence efficiency exceeding 90%. This allows for the determination of the intrinsic exciton-to-dopant energy transfer rate.