Signe Brewster writing for GigaOM:
The leading transparent solar cells work by absorbing as much light as possible outside of the visible range. If a cell absorbs visible light it becomes reflective, rendering it opaque instead of transparent.
At UCLA, researchers are working on cells that absorb infrared light, which can’t be seen by the unaided eye. They announced today that they have created a strip of transparent solar cells that converts 7.3 percent of the solar energy it receives into electricity. That is far below the 15 percent to 20 percent efficiency of conventional solar cells, but it is nearly twice as efficient as the 4 percent UCLA achieved last year.