June 23, 2009
Relay boosts dye solar cells
Add a second dye to a dye-sensitized
solar cell, and you can boost the power output from these low-cost
Dye-sensitized solar cells use dye molecules to absorb energy
from sunlight and pass it on to an inexpensive semiconductor material
that converts it to an electric current. The second dye -- an energy
relay dye -- absorbs higher energy photons than the solar cell normally
absorbs and passes the energy on to the primary dye.
The primary dye coats nanoparticles of the semiconductor material.
Energy relay dye molecules float in an electrolyte surrounding the
nanoparticles. The energy relay dye transfers energy absorbed from
sunlight to nearby primary dye, which also directly absorbs lower-energy
A prototype energy relay dye solar cell converted 26 percent
more light to electricity than the same cell without the energy relay
The prototype has a power conversion efficiency of only 3.21
percent. The technique has the potential to push dye-sensitized solar
cells to about 15 percent, however.
The best dye-sensitized solar cells are about 12 percent efficient.
Commercially available silicon solar cells, which are more expensive,
are typically about 20 percent efficient.
light harvesting in dye-sensitized solar cells with energy relay dyes
Nature Photonics, published online June 21, 2009
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