Nacre-inspired crystallization and elastic "brick-and-mortar" structure for a wearable perovskite solar module

Perovskite solar cells (PSCs) are promising candidates for power sources to sustainably drive next-generation wearable electronics, following the advances in PSCs and future desires of harvesting and storing energy integration. However, the natural brittle property of crystals for elastic deformation restricts the mechanical robustness, which definitely results in degraded efficiency. In fact, the crystalline quality and "cask effect" impact large-area reproducibility of PSCs. Inspired by the highly crystalline and tough nacre, herein, we report biomimetic crystallization to grow high-quality perovskite films with an elastic "brick-and-mortar" structure. The antithetic solubility of the composite matrix facilitates perpendicular micro-parallel crystallization and affords stretchability to resolve the "cask effect" of flexible PSCs. We successfully fabricate PSC chips (1 cm² area) with average efficiencies of 19.59% and 15.01% on glass and stretchable substrates, respectively. Importantly, a recorded 56.02 cm² area wearable solar-power source with 7.91% certified conversion efficiency is achieved. This skin fitting power source shows bendability, stretchability and twistability and is practically assembled in wearable electronics.