Enhanced three-photon absorption excited at near-infrared laser pulses and stability of MAPbBr₃ quantum dots encapsulated in mesoporous single MOF-5 crystals

Organometallic halide perovskites have attracted attention due to their excellent optical properties. However, the inherent instability limits their wide application in the field of optoelectronics. In this study, a distribution immersion method was used to embed MAPbBr₃ perovskite quantum dots into mesoporous MOF-5 microcrystals, constructing an effective host–guest structure. Compared with MAPbBr₃ quantum dots, the MAPbBr₃@MOF-5 composite not only exhibits superior optical performance but also significantly enhanced long-term stability and thermal stability. Nonlinear optical analysis shows that under the excitation of near-infrared femtosecond laser pulses, the MAPbBr₃@MOF-5 composite exhibits significantly enhanced multiphoton absorption capability. Notably, its effective three-photon absorption coefficient (α₃η ≈ (27.4 ± 3.1) × 10⁻⁵ cm³ GW⁻²) is an order of magnitude larger than that of MAPbBr₃. These outstanding characteristics indicate that the MAPbBr₃@MOF-5 composite has great potential for applications in photonics and information communication, especially in the manufacture of multifunctional nonlinear optical devices and future micro–nano photonic integration technologies.