Self-powered NIR-selective dynamic windows based on broad tuning of the localized surface plasmon resonance in mesoporous ITO electrodes

Abstract

Due to their extremely large surface-to-volume ratio, the localized surface plasmon frequency of doped semiconducting nanocrystals can be dynamically and reversibly tuned through by regulating their surface electron density, namely by creating an accumulation/depletion layer at the interface with a suitable electrolyte. We here report the successful implementation of an engineered nanostructured electrode made by Tin-doped Indium oxide colloidal nanocrystals into a set of near infrared selective electrochromic devices exhibiting a wide (and reversible) modulation of the solar transmission, which results larger than 38% in the range between 780 and 2400 nm and maximum variation of 83% at 2000 nm. It is accompanied indeed by a negligible reduction of the luminous transmittance. The most meaningful charging/discharging mechanisms have been investigated at the interface with six different electrolyte formulations within a systematic set of cyclic voltammetry and electrochemical impedance spectroscopy measurements, and the role of faradaic reactions has been ultimately decoupled from that of purely capacitive charging. Finally, a self-powered NIR-selective dynamic window prototype has been realized upon the integration of three series-connected dye-solar-cells onto the same glass pane, which is thus capable of responsively controlling the intensity of incoming thermal radiation and, simultaneously, of generating a surplus electrical power.