Advanced Micro‐OLED Integration on Thin and Flexible Polymer Neural Probes for Targeted Optogenetic Stimulation

Abstract In recent optogenetics, flexible neural probes with integrated high‐resolution light sources are needed for precise neural circuit analysis. This paper presents a novel flexible neural probe with integrated micro‐Organic Light Emitting Diode (OLED)s for the first time. Eight micro‐OLEDs (sizes ranging from 10 × 10 µm 2 to 100 × 100 µm 2 ) and eight recording electrodes are integrated on a flexible SU‐8 substrate, allowing for simultaneous optical stimulation and neural activity recording. An advanced micro‐OLED integration process, utilizing Al₂O₃/parylene‐C encapsulation, achieves a low water vapor transmission rate of 2.66 × 10⁻⁵g m − 2 day −1 , enhancing durability. An indium zinc oxide (IZO)/silver (Ag)/indium zinc oxide (IZO) structure, referred to as an IAI anode, is introduced to improve OLED performance, and a parylene‐C pixel defining layer minimizes crosstalk and enables independent pixel operation. The micro‐OLEDs emit light at 470 nm, suitable for activating channelrhodopsin‐2 (ChR2), with sufficient optical power density (1 mW mm − 2 at 15 V) confirmed through integrating sphere measurements. This innovative OLED probe represents a significant advancement in optogenetics, providing localized high‐resolution stimulation and electrical recording with minimal invasiveness.