Scientists from Princeton University have reported in Nature Photonics that they have used microscopic folds on the surface of photovoltaic material to significantly increase the power output of flexible, low-cost solar cells.
The team reported that the folds resulted in a 47% increase in electricity generation.
To create the folds, the researchers used ultraviolet light to harden a layer of liquid photographic adhesive, a process called curing. By controlling how fast different sections of the adhesive cured, the team was able to introduce stresses in the material and generate ripples in the surface. The shallower ripples were classified as wrinkles and the deeper ones are called folds. The team found that a surface containing a combination of wrinkles and folds produced the best results.
Professor Yueh-Lin (Lynn) Loo, the principal investigator, said that the finely calibrated folds on the surface of the panels channel light waves and increase the photovoltaic material's exposure to light. "On a flat surface, the light either is absorbed or it bounces back, By adding these curves, we create a kind of wave guide. And that leads to a greater chance of the light's being absorbed."
The research team is using photovoltaic systems made of relatively cheap plastic. Current solar panels are typically made of silicon. Plastic is cheaper and less brittle but plastic panels have not been practical for widespread use because their energy production has been too low.
The researchers are aiming to increase that efficiency with the goal of creating a cheap, tough, and flexible source of solar power.