Affordable Smart Windows with Dual‐Functionality: Electrochromic Color Switching and Charge Storage

Abstract

Excessive cost, insufficient optical modulation, and limited functionality are major drawbacks that presently exist in electrochromic smart windows (ECSWs) that are the backbone of zero‐energy buildings. Herein, a solution toward this niche is provided by optimizing various deposition conditions for WO3 sputtering on crackle lithographically fabricated, cost‐effective Al‐mesh overlayed with SnO2. Ultra‐high switching contrast of 90% is accomplished by a decisive choice of parameters i.e., deposition power (5 W cm−2), oxygen flowrate (46 sccm), pressure (2.7 × 10−2 mbar), and film thickness (530 nm) that are imperative for achieving enhanced oxygen deficiency and film porosity. The ECSW displays fast switching with response and recovery time of 11 and 5 s, respectively, which are nearly twice as fast as control ITO‐based device. Additionally, the film holds good cyclic stability with an excellent coloration efficiency of 47 cm2 C−1. As the state‐of‐the‐art, a large‐area smart window (10 × 10 cm2) operable at 2 V is devised engaging WO3 coated Al_SnO2 electrode. The dual‐functionality is demonstrated by employing four series‐connected (5 × 4 cm2, charging time ≈1.5 min) devices to operate a display for 70 min. A device with a quasi‐solid electrolyte is also fabricated, exhibiting improved cyclic stability beyond 2000 cycles.

Ultrathin sputtered NiO films for enhanced electrochromic performance in smart windows

“…The experimental details of ITO sputter deposition on glass substrates can be found elsewhere. 40,41 A Ni target (99.995%) with dimensions 50 cm × 9 cm × 0.3 cm was used for the NiO deposition. Ion assistance cleaned ITO substrates were used for the deposition of NiO thin films, ensuring the removal of surface oxide impurities on ITO substrates.…”

C-Rich Carbon Nitride Conjugated Polymer Enabling Ion-Migration-Induced Precise Electrochromic Display

“…EC displays that reversibly switch between transparency and coloration under electrical stimuli have no requirements for complex control hardware and electrically expensive actuation strategies . They possess the advantages of low power consumption, simple structure, bistability, and high readability under sunlight, making them a great candidate in see-through displays. − Except for the merits of CPs mentioned above, an average of 50% optical contrast renders CP-based EC devices quite fit for see-through displays.…”