In a future where most things in our everyday life are connected through the internet, devices and sensors will need to run without wires or batteries to be practical..
Towards this goal, Swedish researchers have created a new type of dye-sensitized solar cell that could charge our electronics by harvesting light from indoor lamps.
The research—published in Chemical Science—promises to revolutionize indoor digital sensing for smart greenhouses, offices, shelves, packages, and many other ‘smart’ everyday objects that connect to the internet.
According to a statement from Uppsala University, it is estimated that by 2025, many facets of our lives will be mediated through 75 billion devices that connect to the internet—a majority of which will be located indoors.
Broad installation of internet-enabled devices requires them to become autonomous, meaning that they should no longer need batteries or a grid connection to operate. To achieve this, it is crucial to identify a local low-maintenance energy source that can provide power them, especially in ambient conditions.
An Uppsala research team led by Marina Freitag, assistant professor at the Department of Chemistry, has developed new indoor photovoltaic cells that can convert up to 34 per cent of visible light into electricity to power a wide range of Internet of Things (IoT) sensors.
The team has designed novel dye-sensitised photovoltaic cells based on a copper-complex electrolyte, which makes them ideal for harvesting indoor light from fluorescent lamps and LEDs.
The latest promising results establish dye-sensitised solar cells as leaders in power conversion efficiency for ambient lighting conditions, outperforming conventional silicon and solar cells made from exotic materials.
“Knowing the spectra of these light sources makes it possible to tune special dyes to absorb indoor light.
While generating large amounts of energy, these indoor photovoltaics also maintain a high voltage under low light, which is important to power IoT devices,” says Freitag.
Reducing battery waste and energy consumption
In cooperation with the Technical University of Munich, the researchers have further designed an adaptive ‘power management’ system for solar-powered IoT sensors.
In contrast to their battery-limited counterparts, the light-driven devices intelligently feed from the amount of light available.
Computational workloads are executed according to the level of illumination, minimizing energy losses during storage and thus using all light energy to the maximum of its availability.
Combining artificial intelligence and automated learning, the solar cell system can thus reduce energy consumption, battery waste, and help to improve general living conditions.
In the future, scientists expect that billions of IoT devices self-powered by indoor solar cells will provide everything from environmental information to human-machine and machine-machine communications.
Such advanced sensors can further enhance the next wave of robotics and autonomous systems currently in development.