MIT researchers have developed a technique for scalable manufacturing of ultra-thin and lightweight solar cells, which can be seamlessly attached to any surface.
These fabric solar cells can quickly and easily transform any surface into a power source.
Thin, flexible and light solar cells
Six years ago, the MIT ONE Lab team produced solar cells using a novel class of thin-film materials, manufactured using complex vacuum-based processes, which can be expensive and difficult to apply at scales larger than production.
In this new project, the researchers set themselves the task of developing thin-film solar cells that are fully printable, using ink-based materials and scalable manufacturing techniques.
To produce the solar cells, nanomaterials available in the form of printable electronic inks are used. The solar cell structure is coated using a slotted die coater, which deposits layers of the electronic materials onto a prepared released substrate that is only 3 microns thick. Using screen printing techniques, an electrode is finally deposited on the structure to complete the solar module.
The researchers can then peel the printed module, which is about 15 microns thick, from the plastic substrate, forming an ultralight solar array.
However, these thin, self-contained solar modules are difficult to handle and can easily break, making deployment more difficult. To solve this, the MIT team looked for a lightweight, flexible, high-strength substrate to which they could attach the solar cells. They identified the fabrics as the optimal solution, as they provide mechanical resistance and flexibility with little added weight.
The fabric found is a composite that weighs just 13 grams per square meter, known commercially as Dyneema. This fabric is made of fibers that are so strong that they were used as ropes to lift the sunken cruise ship Costa Concordia from the bottom of the Mediterranean Sea. Adding a layer of UV-curable glue, only a few microns thick, they adhere the solar modules to the sheets of this fabric. This forms an ultra-light and mechanically robust solar structure.
“While it may seem simpler to print the solar cells directly onto fabric, this would limit the selection of potential fabrics or other receptive surfaces to those that are chemically and thermally compatible with all the processing steps required to fabricate the devices. Our approach decouples the manufacturing of solar cells from their final integration”explains Mayuran Saravanapavanantham, co-author of the research.
