Problem

Flexible solar cells that are cheap to make could be “printed” on many surfaces, even windows. But the polymers that would be required have so far been lackluster at converting sunlight to electricity. One reason is that unlike more efficient solar materials such as crystalline silicon, polymer-based materials have a messy molecular structure that looks like cooked spaghetti.

Solution

Ying Diao is creating printing techniques that bring order to the otherwise chaotic assembly of plastic molecules. She has made organic solar cells with double the efficiency of previous ones. Diao came up with a microscopic “comb” that controls the flow of the molecules and lets them assemble into orderly structures during printing.

—Ryan Cross