Funnel-shaped precursor engineering for high-performance flexible perovskite photodetectors

• • Detectivity of 19.48×10^12 Jones and on/off current ratio of 6.87×10^4: These metrics exceed typical flexible perovskite photodetectors, enabling high-sensitivity imaging in artificial retina applications where low-light detection is critical. • • 92.53% photocurrent retention after 4000 bending cycles at large angles: This durability threshold addresses the mechanical failure of conventional flexible devices, ensuring long-term operational stability in implantable or wearable systems. • • Ultrathin Pt electrode (<10 nm) with ultra-smooth surface via RF magnetron sputtering and angular ion beam polishing: Reduces electrode discontinuities and crack formation, directly mitigating performance degradation under repeated bending. • • Funnel-shaped PbI2 precursor with dense-gradient vertical structure: Enhances CH3NH3I penetration and perovskite crystallization, yielding large grains and strong interfacial bonding, which are essential for uniform 10×10 array performance and high-resolution imaging.