The trick was to develop “mechanically robust” light-absorbing materials that achieve some of the highest power conversion efficiency of any organic cell, at 13 percent. That’s lower than many conventional solar cells (over 20 percent), but should be enough for wristwear. They’re relatively easy to make thanks to continuous printing tech.
Be sure to temper your expectations. The research team is planning to commercialize the new solar cell tech, but inventions like this can take years to refine and implement. The advantages are clear, at least. This could lead to more wearables that only need small batteries, or none at all. That could keep them running for much longer and slim them down compared to the relatively bulky devices you see today.