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All‐inorganic perovskite (CsPbX3, X = Cl, Br, I) nanocrystals (NCs) with promising optical properties are recognized as a rising star among photoelectric materials, but their inevitable instabilities limit extensive application. Herein, a new one‐step strategy for encapsulating CsPbX3 NCs with porous zeolite via the hot injection method is explored. By altering the mole ratio of PbX2, the emission wavelength of CsPbX3@zeolite is found to be regularly modulated from blue‐emission (CsPbCl2Br@zeolite, 436 nm) to red‐emission (CsPbBrI2@zeolite, 648 nm), thus enabling full spectrum adjustment. Due to the surface passivation of zeolite to CsPbX3 NCs, CsPbX3@zeolite possess an outstanding quantum yield and display excellent thermal/photo/air stability. Subsequently, white light‐emitting diodes based on green‐CsPbBr3@zeolite and red‐CsPbBrI2@zeolite are constructed and applied to the backlit display, achieving a wide color gamut of 134.2% for NTSC 1953 and 99.8% for Rec. 2020. The CsPbX3@zeolite implanted with a polymethyl methacrylate film is used to realize upconversion emission under an 800 nm laser at room temperature. Furthermore, amplified spontaneous radiation based on CsPbBr3@zeolite films is achieved. These results convincingly indicate broad application prospects for CsPbX3@zeolite prepared via this simple method.

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The inherent instability severely limits the applications of cesium lead halide (CsPbX3) perovskite quantum dots (PQDs). Herein, introducing these CsPbX3 PQDs into all-inorganic amorphous solid matrices is a simple and effective encapsulation strategy to achieve prominent chemical stability. In this work, CsPbCl2Br1PQDs are precipitated in borosilicate glasses with the aid of a crystallization control process, followed by the explorations of the optical properties and amplified spontaneous emission (ASE) performance. Our results indicate that the prepared CsPbCl2Br1PQDs-embedded glasses exhibit tunable photoluminescence (PL) emissions and absorption edges by controlling the heat-treatment temperatures. Simultaneously, ASE behaviors of CsPbCl2Br1PQDs-embedded inorganic glasses have been first demonstrated under 800 nm fs laser excitation at room temperature, the threshold reduces from 1.24 to 0.19 mJ/cm2 as the crystallization temperatures increase from 440 to 530 °C. Finally, a robust inorganic glass host can insulate the air from CsPbX3 PQDs, which enables the attainment of CsPbCl2Br1PQDs stability, including better thermostability and photostability. It can be seen that the heat-treatment temperature in the fabrication process is of critical importance in affecting the CsPbX3 PQDs crystallization and quality, which provides a new strategy for laser applications.

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