OLEDs: high-density light sources for high-resolution brain control

Light-based neuromodulation increasingly demands tools that deliver high spatial and temporal resolution, especially for precise stimulation in deep brain regions. OLEDs are uniquely suited for this purpose due to their ultrathin, conformable architecture and compatibility with flexible substrates and CMOS backplanes. Depending on the characteristics of the probe, OLED pixels can be arranged in high-density, arbitrarily shaped, and individually addressable patterns to be tailored to specific experimental requirements. We demonstrate the monolithic integration of blue and orange top-emitting OLEDs on CMOS chips with four shanks (6 mm long, 150 μm wide), containing a total of 1024 pixels (19×21 μm², 24.5 μm pitch). Using plasma-based surface treatment, we achieve >90% yield and emission levels exceeding 0.2 mW/mm²—sufficient for in vivo single-neuron stimulation. This marks a significant step toward chronic, high-density optoelectronic neural interfaces. Additionally, I will present ongoing work adapting the OLED fabrication process to flexible polyimide-based probes and wireless magnetoelectric substrates, broadening the application scope of OLEDs in implantable neurotechnologies.