Self-powered electrochromic window using green electrolyte

Electrochromic windows are considered as future smart windows for conditioning day light inside the room. Most of the electrochromic windows are fabricated using synthetic electrolytes which require an external power source and are also not always environmental friendly. Therefore there is a need for the utilization of naturally occurring electrolytes and also low power consumption devices. We report a self-powered electrochromic window based on naturally occurring gel electrolyte extracted from aloe vera. Prussian blue and aluminum electrode based electrochromic window was fabricated to test the aloe vera gel as electrolyte. A voltage of 0.8 V appeared across the two conducting electrodes of the electrochromic device and light transmittance was found to change from dark to transparent state on self-biasing. The recovery of the device from transparent to dark state with different external voltages was studied. Aloe vera gel was found to be useful as an electrolyte in smart windows, due to its advantages such as low cost, ease of availability and non–toxicity.