Doped perovskite lead halide nanocrystals (PHNCs) are promising materials for various optoelectronic applications, but the major challenge faced by the researchers is the inability to dope foreign elements into perovskite lattice because of the strong lead-halide bond energies. In this work, we have used Fe as a dopant in CsPbCl3 to explore different doping techniques based on the colloidal synthesis of PHNCs to investigate the advantages and disadvantages of different techniques. We are able to dope a relatively higher amount of Fe (∼10%) than reported and observe clear optical signatures when the precursor does not have pre-existing Pb−Cl bonds.Fe2+ is introduced in CsPbCl3 lattice via colloidal synthesis, which stabilizes in the cubic phase of the pristine perovskite. By using a non-ionic precursor to introduce Fe, the effect of Fe levels from the halide ion induced surface passivation can be efficiently decoupled. The introduced acceptor levels via doping traps the excited charge carriers before they radiatively recombine, thus quenching the perovskite photoluminescence. The extent of the quenching depends on the synthesis method and the amount of Fe introduced inside the lattice. We prove that there are two competing processes inside a doped PHNC – one is the effect of dopant energy levels, and the other is surface passivation by halide ions. Using the most optimal synthesis strategy, we show that although Fe does act as a luminescence quencher in perovskite similar to II–VI quantum dots (QDs), the quenching requires much more Fe compared to trace amounts of Fe required in traditional QDs. Our work will assist in giving an overall comparative idea of doping and finding the most optimized strategy and help identify the underlying physical processes in perovskite based QDs.
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