There are many approaches being pursued by various research groups searching for cheaper ways to make photovoltatic solar energy cells for the generation of electricity. One reason that photovoltaics are expensive is that it is expensive to make the highly purified silicon semiconductor material that most existing photovoltaic cells use. Eric McFarland at UC Santa Barbara is pursuing the development of a two layer approach that allows the use of a less pure and therefore much cheaper titanium dioxide semiconductor
The researchers' prototype suggests that the devices would be much less expensive to manufacture than today's solar cells and can be improved to be nearly as efficient. "It's enormously cheaper... more than a factor of 10," said Eric McFarland, a professor of chemical engineering at the University of California at Santa Barbara.
The titanium dioxide serves only as the lower layer charge carrier while a dye serves as a light absorbing layer.
To overcome this problem, McFarland and Jing have developed a multi-layer device that separates the light-absorption and charge-carrier transport processes.
The efficiency of this new type of photovoltaic is low at this stage in development. But McFarland thinks he can raise the effciency and a design that allows the use of much cheaper materials is a great way to make photovoltaics cost competitive.
Electrons excited in the dye shoot through the gold and are collected in the titanium dioxide. Missing electrons in the dye are replaced from the metal. Because the semiconductor does not have to absorb light itself, inexpensive semiconductors will do the job.
|Share |||Randall Parker, 2003 March 25 08:38 PM Energy Solar|