All-solid-state electrochromic device integrated with near-IR blocking layer for image sensor and energy-saving glass application

Abstract

The all-solid-state electrochromic device (ECD) integrated with near-IR (NIR) blocking layer fabricated by reactive DC magnetron sputtering technique has been developed for image sensor and energy-saving glass applications. The all-solid-state ECD with the single-substrate structure of glass/NIR-blocking transparent conductive oxide (TCO)/NiO/Ta2O5/WO3/ITO could potentially modulate the optical transmittance between 81.9% and 17.5% at 550 nm in the visible region and between 38.0% and 9.5% at the NIR wavelength larger than 1100 nm. The better energy-saving and light blocking performance, including the larger optical density difference (ΔOD) and lower solar heat-gain coefficient (SHGC) could be achieved in the NIR-blocking ECD structure, even with the general criteria SHGC(bleach)/SHGC(colored) < 3. With the application of ECDs, it is possible to directly apply the device onto an image sensor and energy-saving glass with the NIR rejection function even in the bleached state. Furthermore, the NIR-blocking TCO with the low sheet resistance and high transparency characteristics also provides the lower power consumption in the switching cycle at voltages as low as 5 V, and makes ECDs the ideal components for applications of large area and battery powered devices.