Engineers have created a wide range of novel and promising electrical devices in recent years. Among these are electrochromic devices (ECDs). They are reversible systems that may control optical properties such as light transmission, absorption, reflection, or emittance. ECDs could have a wide range of uses, including the production of smart windows that increase building energy efficiency, mirrors, and alternate displays for electronic devices.
Solid-state electrochromic devices have been especially promising for the development of smart windows. Nonetheless, it has been discovered that these devices have limited ion diffusion speeds, causing them to colour and bleach relatively slowly over time.
A research group has created a new electrochromic device that can swiftly swap colour, potentially outperforming earlier offered solutions. The study presented a fast-switching electrochromic device based on an all-solid-state tandem structure and employing protons as the diffusing species. The innovative device could propel the Electrochromic Materials Market forward.
The electrochromic material used is tungsten trioxide (WO3), and the solid-state proton source is poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS).
In a series of preliminary tests, the researchers assessed the structure they created. The examination revealed that the device produces highly promising outcomes while having a low contrast ratio. This denotes that it has a slight difference between its on and off transmittance of light). Researchers overcame this constraint by adding a solid polymeric electrolyte layer on top of the PEDOT: PSS layer. This layer effectively supplied sodium ions to the PEDOT: PSS layer while pumping protons into the WO3 layer via an ion exchange process.
The resulting electrochromic devices exhibit high contrast ratios (more than 90 per cent at 650 nm) and fast responses. Further, it also showed good colouration efficiency (109 cm2 C-1 at 670nm) and excellent cycling stability (less than 10% degradation of contrast ratio after 3000 cycles. The fact that they were able to construct these structures shows that their technologies may be utilised to construct smart windows of varying sizes.
The electrochromic devices described by this team of researchers could be introduced and tested in a variety of real-world contexts in the future. Engineers might utilise them to create novel information displays and triple-state optical devices, and smart windows.