Kirigami-Based Highly Stretchable Thin Film Solar Cells That Are Mechanically Stable for More than 1000 Cycles.

Exploiting stretchable solar cells that can accommodate large strain and feature high cyclic mechanical endurance is challenging for wearable and skin-interfaced electronics application. In this work, we demonstrated such solar cells using the kirigami design. Experiments and mechanical simulations showed that the kirigami structure effectively imparted stretchability to perovskite solar cells (PSCs) through out-of-plane deformation, which significantly reduced the stress in devices. The kirigami-based PSCs with optimal geometric parameters exhibited high mechanical deformability, including stretchability (strain up to 200%), twistability (angle up to 450°), and bendability (radius down to 0.5 mm). More importantly, the kirigami PSCs revealed high mechanical endurance with almost unchanged performance even after 1000 repetitive stretching, twisting, and bending cycles. This kirigami design for stretchable PSCs presented here provides a promising strategy to achieve high deformability for solar cells as well as other optoelectronic devices.