Implantable, Biointegrated Optoelectronic Platforms with Ultrathin Encapsulation Layers as Long‐Term Neural Interfaces

Abstract With the increasing demand for advanced biomedical technologies, there is a pressing need for flexible, integrated systems capable of simultaneously detecting and stimulating biological processes with high precision and reliability. In this study, an on‐chip integrated flexible electronic system is successfully fabricated that combines both photoelectric detection and stimulation functionalities. This system integrates single‐crystal silicon nanomembrane (Si‐NM) photodiode array with micro‐all‐inorganic light‐emitting diodes (µ‐ILEDs), achieving comprehensive flexibility and complete encapsulation. The Si‐NM photodiode exhibits broad responsivity across the visible light spectrum. Observed spatial response variations enable the detector array to accurately capture spatial information, precisely determining the position and direction of the light sources. Notably, the system incorporates an ultrathin thermally grown silicon dioxide (t‐SiO 2 ) biofluid barrier. This barrier ensures stable leakage current in the device following 120 h of immersion in 90 °C PBS solution, guaranteeing long‐term stability and reliability. Furthermore, this barrier effectively prevents the infiltration of toxic elements into surrounding tissues, ensuring the safety and biocompatibility of the implant. By leveraging advanced materials and manufacturing technologies, this system not only enhances the performance of optoelectronic devices but also expands their application scope in the biomedical field, opening new avenues for future biomedical research and clinical innovations.