Funnel-shaped precursor engineering for high-performance flexible perovskite photodetectors
Flexible photodetector arrays are critical for artificial retina prosthetics, yet their performance is limited by electrode discontinuities and incomplete perovskite crystallization under mechanical stress. This study introduces a funnel-shaped precursor engineering strategy to fabricate high-performance flexible perovskite photodetectors. An ultrathin platinum electrode film (UTPF) of less than 10 nm thickness is deposited via radio frequency magnetron sputtering combined with angular ion beam polishing, achieving an ultra-smooth surface. A vapor deposition method with dynamically regulated evaporation rates produces a dense-gradient PbI2 precursor with a funnel-shaped vertical structure, facilitating CH3NH3I solution penetration and yielding a dense, uniform perovskite film with large grains and strong interfacial bonding to the UTPF. The resulting devices exhibit a high detectivity of 19.48×10^12 Jones, an on/off current ratio of 6.87×10^4, and retain 92.53% of the original photocurrent after 4000 bending cycles at large angles. Integrated 10×10 flexible photodetector arrays demonstrate uniform dark current and photocurrent, along with high imaging resolution, confirming reliable imaging capabilities. This work addresses the mechanical and crystallization bottlenecks of flexible perovskite photodetectors, offering a viable route for artificial retina and wearable optoelectronic applications.