Hierarchical Ceramic Encapsulation Strategy Enables Robust Perovskite Nanocrystals for Next‐Generation Laser‐Driven Diodes

All‐inorganic perovskite nanocrystals (CsPbBr 3 NCs) are promising for high‐color‐purity optoelectronic devices, yet their instability under operational stressors remains a critical bottleneck. Herein, a hierarchical ceramic encapsulation strategy combining mesoporous silica (SiO 2 ) confinement and zirconia (ZrO 2 ) ceramic coating to achieve ultra‐stable CsPbBr 3 NCs is proposed. The mesoporous SiO 2 framework acts as a nanoreactor for spatially confined NCs growth, while atomic‐layer‐deposited ZrO 2 seals residual micropores and forms a dense, impermeable shell via high‐temperature annealing (300–600 °C). Optimized composites (400 °C‐annealed) retain a high photoluminescence quantum yield (PLQY >85%) and demonstrate record stability: maintain 100% of their photoluminescence value after 720 h under “double‐85” (85 °C, 85% RH) conditions and >65% of initial PL intensity under high‐power laser excitation (200 mW mm −2 , 450 nm) for 108 h. When integrated into laser‐driven white‐light devices, the device achieves an ultra‐wide color gamut (98% Rec. 2020, and 131% NTSC), surpassing state‐of‐the‐art perovskite‐based systems. This dual‐phase hierarchical ceramic encapsulation strategy not only overcome the stability bottleneck of perovskites but also unlocks their potential in high‐energy photonic technologies.