Conducting Polymer‐Based Electrochemically Tunable Filters with Spatiotemporal Spectral Tunability

Abstract Optical filters are key components to achieve spatial or temporal modulators for constructing computational miniaturized spectrometers. Conducting polymer‐based electrochemically tunable filters with spatiotemporal spectral tunability are reported, demonstrating the advantages of angle‐independence, diverse spectral modulation, high repeatability, and flexibility. By controlling the chemical doping of polyaniline solutions and films, diverse spectral modulation is achieved in the wavelength range of 350–1100 nm. To achieve temporal encoding, an electrochemically tunable filter is developed using a three‐electrode vertical device (ITO/PAni/Electrolyte (Ag/AgCl)/PEDOT/ITO), which exhibits continuous spectra with high repeatability during 100 cycles test. To achieve spatial encoding, a three‐electrode lateral device is developed incorporating three different conducting polymers (Cu/Electrolyte (ITO‐PAni+PPy+PEDOT‐OH)/Cu), which show gradient spectra with extensive diversity. Using a three‐electrode vertical device, a miniaturized hyperspectral imaging system with 640 × 512 pixel resolution is constructed, which can distinguish quantum dot solutions with different emission wavelengths of 10 nm. Combining the spectral tunability of a three‐electrode lateral device and a compressed sensing‐based reconstruction algorithm, a miniaturized spectrometer with a spectral resolution of ≈1 nm is further theoretically demonstrated. In summary, conducting polymer provides advanced electrochemically tunable light modulators for smart optics.