South Korea University Creates Foldable Solar Cells

A team of researchers from Pusan National University (PNU) in South Korea have created a prototype transparent conductor for foldable solar cells with the help of single-walled carbon nanotube (SWNT) films. This, they claim, is a promising candidate to help create an efficient, flexible, foldable solar cell device.
Flexible and foldable are distinct from each other, they explain outrightly because a foldable device needs to withstand severe mechanical stresses as those caused by an extremely small bending radius of 0.5 mm. For their research work, they synthesized single‐walled carbon nanotubes (CNTs)–polyimide (PI) composite film with a thickness of 7 µm and used it as a foldable transparent conductor in perovskite solar cells (PSCs).
The resulting material was doped using MoOx to increase its conductivity with the aim to ensure maximum performance. "The ultrathin foldable transparent conductor exhibits a sheet resistance of 82 Ω sq.⁻¹ and transmittance of 80% at 700 nm, with a maximum‐power‐point‐tracking‐output of 15.2% when made into a foldable solar cell. The foldable solar cells can withstand more than 10,000 folding cycles with a folding radius of 0.5 mm," reads their research work.
In other words, this 7 micrometers thick prototype offered 80% transparency and a power conversion efficiency of 15.2% which the researchers believe is the highest ever achieved in solar cells using carbon nanotube conductors.
These results open up a door of opportunity to create next-generation solar panels as these foldable devices can be applied to solar cells, and integrate these into everyday items. PNU Research team head Professor Il Jeon said, "The obtained results are some of the best among those reported thus far for flexible solar cells, both in terms of efficiency and mechanical stability."
The research work titled Foldable Perovskite Solar Cells Using Carbon Nanotube-Embedded Ultrathin Polyimide has found its way to the scientific journal Advanced Science.