Enduring Luminescence: Water and Heat Stable Perovskite Films via Hierarchical Hydrophobic Encapsulation

Lead halide perovskite nanocrystals have emerged as highly promising materials for optical devices due to their high photoluminescence quantum yield, excellent color purity, and low stimulated emission thresholds. However, one of the significant challenges limiting their practical application is the instability of nanocrystal films under various environmental conditions and elevated temperatures. In this study, we present a stabilization strategy involving the deposition of CsPbBr₃ nanocrystals onto a template composed of a silica layer grown on a low-cost, soot-derived carbon skeleton, followed by hydrophobic encapsulation using polydimethylsiloxane (PDMS). The resulting thin films exhibited hydrophobic characteristics with a water contact angle exceeding 146.8°, retained high photoluminescence stability for up to 40 days in ambient air and 36 days under water, and demonstrated thermal resistance up to 100 °C. The incorporation of PDMS created a reliable moisture barrier, greatly boosting the perovskite layer's resistance to environmental degradation. The results demonstrate that our approach offers a viable strategy for developing long-lasting and environmentally robust coatings for perovskite-based devices.