Skin-conformal MHz-speed organic photodetectors for angle-free and long-range near-infrared communication

Near-infrared (NIR) organic photodetectors (OPDs) offer a promising platform for skin-integrated optical communication systems, but achieving high-speed operation under mechanical stress remains a central obstacle. Here, we report a skin-conformable OPD with a 3 μm total thickness that achieves a specific detectivity calculated from noise-equivalent power of 0.84 × 10¹⁴ Jones at 790 nm and a - 3 dB cut-off frequency exceeding 1 MHz, maintained under 66% compressive strain and sub-5 μm bending radius. This performance is enabled by an engineered Br-functionalized PACz hole transport layer, which facilitates efficient charge extraction without compromising mechanical resilience. When conformally mounted on human skin, the device supports angle-independent responsivity across a 0-90° range and enables wireless reception of audio-modulated signals from a 100 m distant source with a bit-error rate of 10^-3. These results define a new performance regime for ultrathin, deformable NIR photodetectors by overcoming the trade-off between speed and flexibility, and demonstrate their scalable integration into skin-mounted, interactive communication systems.