Mechanically reinforced quasi-2D perovskite films via SEBS incorporation for flexible photodetector applications

Quasi-two-dimensional (quasi-2D) perovskites hold promise for flexible optoelectronics but suffer from mechanical brittleness. Here, we enhance their flexibility by incorporating a styrene-ethylene-butylene-styrene (SEBS) triblock copolymer during antisolvent-assisted crystallization. The resulting composite films exhibit ~100× lower Young's modulus and wrinkled morphologies that boost light absorption. SEBS also suppresses low-n phases, improving charge transport. Photodetectors based on these films achieve a responsivity of 0.27 A/W and detectivity of 1.23 × 1012 Jones at 740 nm, with 93% responsivity retained after 10,000 bending cycles. This scalable strategy enables robust, high-performance flexible perovskite devices.