mixture at 150 °C for 2 min and then Cs-oleate solution (0.4 mL in ODE) was quickly injected. After 5 s, the reaction mixture was cooled by the ice-water bath to room temperature.

The further practical applications of halide perovskite quantum dots (QDs) are blocked by problems of instability and nonradiative Auger recombination manifested as photoluminescence blinking. Here, single core/shell structured perovskite semiconductor QDs are successfully fabricated by capping CsPbBr3 QD core with CdS shell. It is demonstrated that CsPbBr3/CdS core/shell QDs exhibit ultrahigh chemical stability and nonblinking photoluminescence with high quantum yield due to the reduced electronic traps within the core/shell structure. Efficiency of amplified spontaneous emission exhibits obvious enhancement compared to that of pure CsPbBr3 QDs, originating from the mitigated competition between stimulated emission and suppressed nonradiative biexciton Auger recombination. Furthermore, low‐threshold whispering‐gallery‐mode lasing with a high‐quality factor is achieved by incorporating CsPbBr3/CdS QDs into microtubule resonators. Density functional theory (DFT)‐based first‐principles calculations are also performed to reveal the atomic interface structure, which supports the existence of CsPbBr3/CdS structure. An interesting feature of spatially separated charge density at CsPbBr3/CdS interface is found, which may greatly contribute to the suppressed Auger recombination. The results provide a practical approach to improve the stability and suppress the blinking of halide perovskite QDs, which may pave the way for future applications for various optoelectronic devices.

Recent years have witnessed a surge of research in all-inorganic perovskite nanomaterials for solar cells and light emitting diodes due to their higher chemical stability compared to their hybrid organic-inorganic counterparts. Herein, by combining material synthesis, characterization, optical measurement, and density functional theory based first principles calculation, a type of all-inorganic perovskite CsPb 2 Br 5 microplate with superior crystallinity, enhanced stability, and tunable optical properties is reported. With a robust band gap of ≈2.44 eV, CsPb 2 Br 5 microplate exhibits low-threshold amplified spontaneous emission under both one-and two-photon excitation, which is related to its unique spatially distinguished valence/conduction band edge states originating from the intrinsic sandwiched structure. These results are expected to shed new light on future design and development of novel perovskite nanomaterials for optoelectronic devices.

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