1：Experimental Design and Method Selection:

The study employed a pore-encapsulated solvent directed (PSD) approach to synthesize HBP nanocrystals (NCs) stabilized within ZIF-8 MOF at room temperature. This method involves dissolving precursors in a solvent mixture, adding a less polar solvent for nucleation, and washing and drying the composites.

2：Sample Selection and Data Sources:

Samples included MAPbBr3, EAPbBr3, and mixed cation perovskites encapsulated in ZIF-8. Precursors were purchased from Sigma-Aldrich and Spectrochem, and synthesized as per literature methods.

3：Precursors were purchased from Sigma-Aldrich and Spectrochem, and synthesized as per literature methods. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included Bruker D8 Advanced X-Ray diffractometer for PXRD, Perkin Elmer Optima 7000dv for ICP-AES, Perkin-Elmer STA6000 for TGA, Zeiss Ultra Plus FESEM for morphology, Horiba Fluorolog-3 for PL, Edinburgh Instruments FLS 980 for TCSPC, Shimadzu UV3600 for UV-Vis, Spectroline ENF-240C/FE UV light, JEM-2100F HRTEM for TEM, Thermo K-alpha for XPS, BELSORP-max and BELSORP-aqua3 for gas sorption, and Quanta-Phi integrating sphere for PLQY. Materials included PbBr2, HBr, Zn(NO3)2·6H2O, methylamine, ethylamine, n-octylamine, 2-methylimidazole, and various solvents.

4：Experimental Procedures and Operational Workflow:

Synthesis involved stirring precursors in MeOH/DMF, adding toluene, filtering, washing with DMF and water, and drying at 120°C. Stability tests included immersion in solvents for 90 days, UV irradiation for 20 days, and heating at elevated temperatures. Photocatalysis experiments used a 60W LED lamp to degrade pollutants like methyl orange.

5：Data Analysis Methods:

Data were analyzed using PXRD for structural integrity, ICP-AES for Pb leaching, PL spectra for luminescence, UV-Vis for absorption, and statistical methods for decay profiles and quantum yield calculations.