An international team led by KAUST envisions that new thin-film device technologies based on alternative semiconductor materials such as printable organics, nanocarbon allotropes and metal oxides could contribute to a more economical and environmentally sustainable Internet of Things (IoT).

The Internet of Things should affect daily life and many industries. Remote-controlled home security systems connect and facilitate data exchange between a large number of smart objects of all shapes and sizes, such as driverless cars equipped with sensors that detect road obstacles, and temperature-controlled factory equipment around the world. . Internet and other sensor and communication networks.

In the next decade, this emerging hypernet is expected to reach trillions of devices and increase the number of sensor nodes deployed on its platforms. Current approaches to powering sensor nodes rely on battery technology, but batteries need to be replaced regularly, which is expensive and harms the environment over time.

Additionally, the current global production of lithium for battery materials may not be able to keep up with the increasing energy demand due to increased sensors. Wirelessly powered sensor nodes can help create a sustainable IoT by harvesting energy from the environment using so-called energy harvesters such as photovoltaic cells and radio frequency (RF) energy harvesters, among other technologies. Wide area electronics can play an important role in the use of these power supplies.

KAUST alumni Kalaivanan Loganathan, together with Thomas Anthopoulos and colleagues, evaluated the feasibility of various large-area electronic technologies and their potential to create environmentally friendly, wirelessly-operated IoT sensors. Large-area electronics has recently become an attractive alternative to traditional silicon-based technologies, thanks to significant advances in solution-based processing that makes it easy to print devices and circuits on large-area flexible substrates. They can be produced at low temperatures and on biodegradable substrates such as paper, making them more environmentally friendly than their silicone-based counterparts.

Over the years Anthopoulos’ team has developed a number of radio frequency electronic components, including semiconductor devices based on metal oxides and organic polymers, known as Schottky diodes. “These devices are the most important components of wireless energy harvesters and ultimately determine the performance and cost of the sensor nodes,” Loganathan says.

The main contribution of the KAUST team includes fabrication methods for scalable RF diodes for energy harvesting reaching the 5G/6G frequency range. “These types of technologies provide the necessary building blocks for a more sustainable way to power billions of sensor nodes in the near future,” Anthopoulos says. The team is investigating the integral integration of these low-power devices with antennas and sensors to demonstrate their true potential, adds Loganathan.