Engineers at MIT are tinkering with all sorts of advanced solar power technology, like self-assembling solar cells, virus-structured cells and an artificial leaf system that mimics photosynthesis. Their latest project is somewhat more simple: It can be printed on a regular sheet of paper.
The cell is tough enough to work even after being folded into a paper airplane — unlike many "flexible" cells, it's not merely bendable, but foldable as well. It’s made using a relatively simple vapor deposition process, rather than the typical high-temperature etching process used to make solar cells.Like the silver ballpoint pen we saw earlier this month, the system uses a 3-D printing technique to deposit materials onto a surface. The process is a little more complex than using a printer, however, because it requires five layers of material and a stencil to form the patterns of the cells. It also has to be done in a vacuum chamber, so it’s probably not doable for the average DIY-er.
But as MIT News points out, the vapor deposition process is widely used throughout various industries — it’s similar to the process used to make the silver lining in bags of potato chips — so it can be done on a large scale at low cost.
To test their technology, engineers led by chemical engineering professor Karen Gleason folded a paper photovoltaic cell into a paper airplane, and the cell still collected energy from sunlight. They also printed one on a piece of plastic, like the kind used to make soda bottles, and folded that one 1,000 times. It still worked, while a traditionally-produced cell on the same plastic failed after just one fold.
The team even printed a cell on a piece of paper, and then put that paper in a regular laser printer to see what would happen. It still worked, even after a laser-heated layer of toner ink was printed on top of it. In tests, the folded cells were still able to gather ambient sunlight to power a clock and other devices.
They are not that efficient — a paltry 1 percent — but the researchers think that will improve as they fine-tune the “ink” and the deposition process. But even now, “it’s good enough to power a small electric gizmo,” said engineering professor Vladimir Bulović. Watch a demonstration below.
Foldability is important for portable, cheap circuits — a circuit or PV cell that can withstand being crumpled in a pocket would be a major advancement for portable devices. But the lightweight nature of this cell may be its biggest breakthrough. Functional photovoltaic cells printed on paper or thin plastic could have a host of uses, from lightweight battery technology to portable power for developing countries.
The research is reported in this week’s issue of the journal Advanced Materials.
The incredible innovations, like drone swarms and perpetual flight, bringing aviation into the world of tomorrow. Plus: today's greatest sci-fi writers predict the future, the science behind the summer's biggest blockbusters, a Doctor Who-themed DIY 'bot, the organs you can do without, and much more.