A team of Indian scientists have developed novel smart window technologies that operate without the need for external electrical energy, enhancing both their energy efficiency and functionality.
Existing electrochromic smart window technologies require external power to function, allowing them to change color from transparent to blue and vice versa when an electrical stimulus is applied. While effective at blocking visible and near-infrared radiation—thus lowering room temperatures—these technologies are often cost-prohibitive due to the expensive materials and processes involved.
However, researchers led by Dr. Ashutosh K. Singh at the Centre for Nano and Soft Matter Sciences (CeNS), an autonomous institute under the Department of Science & Technology (DST), have addressed these limitations through two key studies.
In the first study, the team eliminated the reliance on external electrical power for electrochromic devices. In the second, they made the fabrication process more affordable. The result is a self-powered electrochromic smart window that operates using energy stored during its switching from transparent to colored states, significantly improving its energy efficiency, affordability, and functionality.
Supported by the DST under the "Advanced Materials Technology (AMT)" program, this research focused on developing affordable electrochromic window technology in India.
The team created a device that stores electrical energy by changing color in response to a small electrical stimulus generated by electrochemical reactions occurring within the device itself. This technology is known as the Redox Potential-Based Self-Powered Electrochromic (RP-SPEC) device, commonly referred to as self-powered smart windows.
In its colored state, the RP-SPEC device blocks both visible light and near-infrared (NIR) radiation, leading to significant reductions in room temperature and power consumption. The device is constructed using tungsten oxide (WO3) electrochromic film, vanadium-doped nickel oxide (V-NiO) as the ion storage film, and aluminum as the anode, all coated on a single sheet of tin-doped indium oxide (ITO). This innovative design eliminates the need for an ITO-based counter electrode, making the device more cost-effective.
The research is published in the journal ‘Small’.
"The development of these electrochromic devices represents a major step towards sustainable energy utilization in buildings. By optimizing the process parameters and adopting cost-effective materials, we have created devices that not only enhance energy efficiency but also offer scalable and affordable solutions for modern infrastructures," Dr. Ashutosh K Singh pointed out.
