Stretchable high-fill-factor silicon-liquid metal platform for multilevel visual acquisition and depth sensing.

High-density stretchable pixelated electronics that conform to complex, non-developable surfaces are key enablers of next-generation robotic vision systems, skin-mountable sensors and wearable electronics. Existing strategies for stretchable pixelated device arrays-such as buckling mechanics, pop-up structures, serpentine interconnects and kirigami designs-have offered partial solutions. However, a strategy that simultaneously achieves high device performance, stretchability, fill factor and integration density has remained elusive. Here we present a next-generation platform for stretchable pixelated electronics that integrates high-performance single-crystalline silicon pixels with finely patterned liquid metal interconnects on ultrathin elastomeric substrates. We developed a monolithic microfabrication strategy that enables customizable, densely packed and mechanically compliant pixelated device arrays. Using this platform, we demonstrate shape-reconfigurable imaging devices that achieve superb fill factors of up to 81% and a biaxial stretchability of 100%. We also present a human-eye-inspired robotic vision system with tunable focus and a skin-mountable lens-free imaging system. The complementary operation of retinal and epidermal imaging systems enables multiscale visual acquisition and depth sensing.