Low-Powered, Full-Color Reflective Display based on Electrochromic Resonator

Dynamically tunable reflective display is attractive for their applicability, due to high energy efficiency and clear outdoor visibility. While many reflective displays have been demonstrated, its monochromic color and high operating voltage are remained challenges and restricted their use in diverse electronics. Here, we introduce the full-colored monopixel reflective display (FMRD), which is achieved through a dual cavity structure with active material and lossy medium. As an active layer, polyaniline (PANI) forms a resonant cavity capable of changing its optical properties within a voltage range of -0.2 V to 0.8 V. To obtain a clear reflective color, we enhance light-matter interaction through impedance- matching between lossy medium and active layer. By designing porosity of lossy material with glancing angle deposition, it can be obtained and exhibits a deep reflectance dip. Additionally, the device successfully achieves the generation of the full red-green-blue (RGB) colors within a single pixel. FMRD is maintained half a day without power supply and reactivated its vivid colors after 4 months because self-passivation layer prevents the germanium oxidation. The protonation-based redox reaction plays a crucial role in achieving a fast response, with a rising time of 34 ms and a falling time of 171 ms. The photonic resonator operates at only 0.42 mW/cm² per cycle and demonstrates scalability by addressing 25 pixels in a 5×5 matrix, indicating its applicability for larger-scale metrics.