Liquid Metal Interconnects Overcome the Fill-factor Limitations of Stretchable Pixelated Electronic Devices
Stretchable pixelated electronic devices face a fundamental design conflict: accommodating mechanical deformation while preserving a high fill factor of active photosensitive elements. Conventional strain-relief strategies, such as pop-up, serpentine, and kirigami structures, rely on geometric unfolding that inevitably consumes inactive area, reducing pixel density and compromising photoresponse intensity, spatial resolution, and signal-to-noise ratio. In a recent breakthrough published in Nature Materials, Park et al. demonstrated a high-fill-factor silicon–liquid metal pixelated platform for multiscale visual acquisition and depth perception. The device integrates ~700-nm-thick ultrathin single-crystalline silicon photodiodes, finely patterned liquid metal interconnects, and a styrene–butadiene–styrene (SBS) elastomer substrate. The silicon pixels provide high-performance photoelectric conversion, while the liquid metal interconnects accommodate deformation, achieving a functional separation that mitigates the trade-off between pixel density and mechanical compliance. The device maintains stable photodiode characteristics and repeatable photoresponses under high-curvature hemispherical stretching and large biaxial tensile strain. Two applications were demonstrated: a human-eye-inspired robotic vision system with a curved photosensitive surface for wide-field imaging, and an epidermal, lensless, near-contact imaging device for close-range image acquisition. These systems enable multiscale visual acquisition and depth perception, offering a scalable route for future stretchable visual electronics.