Flexible and controllable piezo-phototronic pressure mapping sensor matrix by ZnO NW/p-polymer LED array

A functional tactile sensing device is essential for next-generation robotics and human-machine interfaces technologies, since the emulation of touching requires large-scale pressure sensor arrays with distinguishable spatial-resolution, high sensitivity, and fast response. Here, a flexible LED array composed of PEDOT:PSS and patterned ZnO NWs with a spatial resolution of 7 μm for mapping of spatial pressure distributions is designed and fabricated. The emission intensity of the LED array sensor matrix is dominated by locally applied strains as indicated by the piezo-phototronic effect. Therefore, spatial pressure distributions are immediately obtained by parallel-reading the illumination intensities of the LED arrays based on an electroluminescence working mechanism. A wide range of pressure measurements from 40 to 100 MPa are achieved through controlling the growth conditions of the ZnO nanowire array. These devices may find prospective applications as electronic skins by taking advantage of their high spatial-resolution, flexibility, and wide pressure mapping range.