Organic Solar Cells Expected to Power the Future?
The concept of the “internet of things” revolves around the idea that objects are interconnected in a global network and can be managed so that they seamlessly support your daily routine. An example of an application of this concept is Tesla’s Powerwall, which powers your household and is programmed to store excess solar energy for later use --all potentially done in communication with other devices. The Internet of Things is making other amazing advancements in solar applications possible. As reported in a recent The Conversation article, these tiny solar panels are worth a look. Here’s the excerpt:
It could herald a great leap forward in the way we live our lives. The internet of things, the idea that objects can be interconnected via a global network, will run your home, keep you healthy and even check how much food is in your fridge. It will mean a trillion new “smart sensors”being installed around the world by 2020. But what’s going to power these devices?
In some cases, the energy source is obvious: sensors in fridges or traffic lights can simply tap into mains electricity. But it’s much trickier to power something that detects water quality in remote reservoirs, cracks in railway lines, or whether a farmer’s cows are happy and healthy.
Organic solar panels might be the answer. They’re cheap, and are flexible enough to power minuscule sensors whatever their shape. The cells can be just two micrometres thick – around a 50th the width of a human hair – but they are able to absorb a huge amount of light for such a thin surface.
These organic photovoltaics (OPVs) differ from silicon solar cells as they can be made entirely from specially-synthesised organic materials, which are deposited onto cheap substrates such as PET, a form of polyester also used in soft drink bottles and crisp packets. This material is lighter, more flexible and can even be tuned to provide different colours – who said solar cells have to be plain black?
Critically, it takes just one day for OPVs to earn back the energy invested in their manufacture, known as the “energy payback time”, which compares to around one to two years for regular silicon solar cells.
Organic photovoltaics can also be moulded onto 3-D surfaces such as roof tiling or even clothing. In our latest research, colleagues and I demonstrated that this makes them more effective at capturing diffuse or slanting light. This wouldn’t make much difference for a regular solar farm in a sunny country, but cloudier places at higher latitudes would see benefits.
For the internet of things, however, these improvements are a game-changer. Few of those trillion sensors will be placed conveniently in the sunshine, facing upwards; far more will be in unusual locations where light only falls indirectly. Tiny organic solar cells will enable energy to be captured throughout the day, even indoors or when attached to clothes.