Super-hydrophobic CsPbX3 (X=Cl, Br, I) perovskite nanocrystals membranes based on bionic lotus leaf interface

Metal halide perovskite nanocrystals (PNCs), particularly all-inorganic CsPbX 3 (X = Cl, Br, I), exhibit exceptional optoelectronic properties, positioning them as revolutionary materials for LEDs, displays, and photodetectors. However, their commercialization is impeded by environmental instability under moisture, heat, and light. To address this, we introduce a solvent-induced surface rheological engineering (SISRE) strategy to fabricate super-hydrophobic CsPbX 3 -PS composite membranes inspired by the lotus leaf effect. Key innovation lies in controlled spraying of a THF/ethanol mixture (3:1 v/v) onto the membrane surface. THF selectively dissolves surface PS to induce micro/nano hierarchical roughness, while ethanol triggers rapid polymer re-solidification. By modulating spray passes (5–15 cycles), we achieved tunable hydrophobicity with contact angles increasing from 70° to >140° (Cassie-Baxter state), while maintaining PLQY∼72% for CsPbBr 3 PNCs membrane. The optimized super-hydrophobic membrane (12 spray cycles) nearly exhibited a 2.7-fold enhancement in water stability (PLQY decay rate: 1.65%/day vs. 4.46%/day for untreated films). In addition, when applied as a down-conversion layer on blue LEDs (λ peak  = 452 nm), the device achieved 111% NTSC color gamut coverage (98% Rec.2020) with CIE coordinates (0.328, 0.288) and CCT = 5722 K. This work provides a scalable, appliable route to concurrently enhance environmental stability and optoelectronic performance of PNCs.