Using Mn-doped CsPbCl3 nanocrystals (Mn:CsPbCl3 NCs) to improve perovskite’s properties is becoming an important strategy. Here, we demonstrate a modified supersaturated recrystallization route to synthesize high-quality Mn:CsPbCl3 NCs at room temperature. Unprecedentedly, sulfonate ligands with various concentrations are shown to successfully tune the dual-color emission of Mn:CsPbCl3 NCs. Ultrafast transient absorption studies reveal that the host-to-dopant internal energy-transfer process involves the mediated traps. Interestingly, the dual-color emission is tuned via stabilizing mediated traps with a small amount of ligand (band edge (BE) emission reduces and Mn2+ emission increases), passivating the deep traps with a large amount of ligand (Mn2+ emission increases), and destroying Mn:CsPbCl3 NCs with too much ligand (both BE and Mn2+ emission is quenched). Furthermore, the ligand tuning Mn2+ emission exhibits quenching for Cu2+ with high sensitivity and selectivity. Our work provides a new strategy to tune the optical properties of Mn:CsPbCl3 NCs and presents its potential application in an optical detector.

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Doping metal ions into lead halide perovskite nanocrystals is one of the most efficient strategies to control their photoelectric properties. Here, we develop a simple and low-cost route to synthesize the high-quality alkaline-earth metal ion (AE 2+ )-doped CsPbBr 3 nanocrystals at room temperature. The almost 100% promoted photoluminescence quantum yield behavior of AE 2+ -doped CsPbBr 3 nanocrystals is demonstrated by an ultrafast dynamics study and theoretical calculations on the dopant defect formation energies and electronic properties. The AE 2+ dopants can promote the radiation recombination of carriers by essentially reducing the carriers trapped into intraband and interband defect states and promote the intraband coupling. Furthermore, Br − and Pb 2+ vacancies can be eliminated to enhance the short-range order of the CsPbBr 3 lattice and enrich the conduction band edge states, leading to the photoluminescence enhancement of CsPbBr 3 nanocrystals. Our studies provide new insights into the mechanism of AE 2+ -doped effects and present guiding strategies for improving the optical performance of doped perovskite nanocrystals.

Sluggish sulfur redox reaction (SROR) kinetics accompanying lithium polysulfides (LiPSs) shuttle effect becomes a stumbling block for commercial application of LiS battery. High‐efficient single atom catalysts (SACs) are desired to improve the SROR conversion capability; however, the sparse active sites as well as partial sites encapsulated in bulk‐phase are fatal to the catalytic performance. Herein, high loading (5.02 wt.%) atomically dispersed manganese sites (MnSA) on hollow nitrogen‐doped carbonaceous support (HNC) are realized for the MnSA@HNC SAC by a facile transmetalation synthetic strategy. The thin‐walled hollow structure (≈12 nm) anchoring the unique trans‐MnN2O2 sites of MnSA@HNC provides a shuttle buffer zone and catalytic conversion site for LiPSs. Both electrochemical measurement and theoretical calculation indicate that the MnSA@HNC with abundant trans‐MnN2O2 sites have extremely high bidirectional SROR catalytic activity. The assembled LiS battery based on the MnSA@HNC modified separator can deliver a large specific capacity of 1422 mAh g−1 at 0.1 C and stable cycling over 1400 cycles with an ultralow decay rate of 0.033% per cycle at 1 C. More impressively, a flexible pouch cell on account of the MnSA@HNC modified separator may release a high initial specific capacity of 1192 mAh g−1 at 0.1 C and uninterruptedly work after the bending‐unbending processes.