Professor Kyung Cheol Choi from the School of Electrical Engineering developed a self-powered textile-based washable polymer solar cell for wearable devices. Recently, textile-based electronics have been scrutinized due to their potential in everyday applications. In fact, there has been enough technological advancement for textile based devices to be operated with low energy consumption, using its environment as a source of energy.
Despite such advancement in flexible solar cell technology for textiles, smart-clothing developers always have had trouble creating clothes with “effective operating lifetimes under aqueous environments”. To realize the full potential of textile electronics, high stability in aqueous environments and durable thin-film encapsulation are necessary. In response, Professor Choi discovered that using silicon dioxide (SiO2) polymer composites along with atomic layer deposited aluminum oxide (ALD-Al2O3) can effectively create a self-powered, washable, and wearable device.
Aluminum oxide is currently widely used to encapsulate electronic devices, preventing degradation of the polymers. However, in aqueous environments, this barrier deteriorates and forms crystals of aluminum. These crystals increase the volume and the total thickness of the device, creating paths for moisture and oxygen to enter the device. Professor Choi discovered that silicon dioxide can react with the aluminum oxide before the crystallization occurs, thereby preventing the deterioration.
In the case of self-powered cells, desensitized solar cells (DSSCs) and polymer solar cells (PSCs) have been strong candidates for application to wearable devices. Although DSSCs are more energy efficient, PSCs were used in Professor Choi’s investigation due to their light weight, flexibility, and durability; even with periodic washing, PSCs can last more than 30 days, with only 2% of damage from its original condition. In addition, the encapsulating device operated stably with a low curvature radius of three millimeters and boasted high reliability.
Energy and Environmental Science magazine recognized Professor Choi’s innovative development and published his research on their January cover page. This discovery can help propel the commercialization of wearable devices as it highlights their durability and efficiency.