Electroluminescent Display Based on Field-Interactive Microparticles for Camouflage and Environmental Monitoring

The development of displays that mimic the color-changing ability and external stimulus-sensing ability of biological skins is of significant interest for emerging robotics and biomedical applications. Here, we present an alternating-current (AC) electroluminescent display that can change the area, color, and luminance by using microparticles which interact with electric and acoustic fields. Dielectrophoretic force produced by AC electric field controls the amount and area of percolated carbon particles that form a conductive gate, enabling light emission from the ZnS phosphor-doped polymer layer. Different stacking combinations of emissive layers enable a wide-range color tuning in a single device by varying the electric field, which may be suitable for camouflage when integrated into the skin of soft robots. The display is also capable of sensing acoustic waves and visualizing the information by luminance change as the conductive gate collapses. Arrays of acousto-interactive displays were successfully used for environmental monitoring and non-destructive testing, where defects, air bubbles, and obstacles inside structures and fluid channels were visualized due to acoustic impedance mismatch. Our platform provides a path forward to engineer active camouflage and displays for soft machines.