Multifunctional integrated electrochromic device by p-n conductive polymers for self-powered smart windows and miniaturized spectrometers

Electrochromic devices enable dynamic modulation of light and heat, yet their broader adoption is hindered by limited color tunability, slow switching kinetics, and low coloration efficiency. Here, we present a complementary organic electrochromic device that addresses these challenges by employing dual conductive polymers: poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) and poly(benzodifurandione). The resulting device delivers exceptional performance, featuring a high optical contrast of 51% at 570 nm, ultrafast switching speeds (0.17/0.36 s for coloration/bleaching), a record-high coloration efficiency (1688 cm² C⁻¹ at 550 nm), and excellent cycling stability over 10,000 cycles. By integrating the device with a semitransparent organic solar cell, we realize a fully self-powered smart window with reducing indoor temperatures by 7 °C. Furthermore, coupling the electrochromic filter with a 4 × 4 organic photodetector array featuring on-chip Fabry-Pérot cavities enables a miniaturized spectrometer with 7.2 nm spectral resolution. This multifunctional electrochromic platform seamlessly bridges smart-window technology and spectral sensing, paving the way for energy-efficient, and compact optoelectronic systems.