Dual-Sensing Electroluminescent Display Based on Dielectrophoretic-Acoustophoretic Self-Assembly

Despite the development of technologies utilizing dielectrophoretic (DEP) or acoustophoretic force, dynamic visualization of these forces is rarely explored and remains challenging. Here, we introduce a dielectrophoretic-acoustophoretic dual-sensing electroluminescent display, which direct force visualization is achieved by self-assembly of conductive carbon micro and nanoparticles. The display comprises coplanar electrodes separated by a gap, a polymer composite with electroluminescent (EL) phosphors, and a chamber with field-responsive conductive particles suspended in a medium. When AC field is applied between the coplanar electrodes, DEP force is induced, and the particles migrate towards the electrode gap, forming dendrites that act as a conductive electrode bridge. EL is triggered from the phosphors, and the intensity and area of EL emission is determined by the magnitude of the applied DEP force. Conversely, when ultrasound generated from a surface acoustic wave device is transmitted to the display, the particles are pushed towards the pressure nodes of the standing acoustic wave, detached from the electrode gap. Destruction of the conductive electrode bridge deactivates EL emission, and the response of the display changes by the frequency and intensity of the given acoustic wave. The display can be integrated with existing surface acoustic wave sensors for visualizing temperature changes. Additionally, the display is further demonstrated for motion tracking or non-invasive monitoring of microfluidic channels. Altogether, our platform outlines a strategy of direct force visualization with particle manipulation, holding great potential for a variety of applications in the fields of electronics and biomedicine.