The mid-wave infrared (MWIR) spectral range (λ = 3–8 μm) enables a variety of important sensing and imaging applications, including non-invasive bioimaging, night vision, and autonomous navigation. However, commercial MWIR photodetectors are largely limited to rigid imaging systems based on heteroepitaxial materials. Consequently, there is a growing demand for mechanically flexible MWIR imagers that can expand their functionality and practical applicability.
Recently, photodetectors based on van der Waals (vdW) black phosphorus (BP) flakes have demonstrated highly sensitive room-temperature photodetection. In addition, vdW materials are solution-processable, which enables scalable processing and facilitates the fabrication of flexible devices.
In this work, we present flexible MWIR imagers composed of photodiodes fabricated on thin plastic substrates using BP ink films. The devices exhibit mechanically robust performance, maintaining responsivity at bending radii down to 2.5 mm and after 5000 bending cycles. Leveraging this mechanical flexibility, we further demonstrate full-azimuthal imaging capability, enabling precise detection of directional light sources.
These results establish a scalable approach for large-area, conformable MWIR imaging and provide a pathway toward integration with flexible electronic systems.
Project currently funded by: Federal